List of medicinal plants
This article aims to analyze medical claims made for herbs and list potential adverse effects they are known to have. The list will always be incomplete, given the vast number of herbs.
“”Herbal products such as St. John's wort are classified as dietary supplements by the U.S. Food and Drug Administration (FDA). The FDA's requirements for testing and obtaining approval to sell dietary supplements are different from its requirements for drugs. Unlike drugs, herbal products can be sold without requiring studies on dosage, safety, or effectiveness.
The quality of herbal products is often unpredictable. Products can differ in content not only from brand to brand, but from batch to batch. Information on labels may be misleading or inaccurate.In addition, "natural" does not necessarily mean "safe." Many natural substances can have harmful effects–especially if they are taken in large quantities or if they interact with other supplements or with prescription medicines.
|—National Center for Complementary and Alternative Medicine|
Herbal remedies vary greatly in efficacy, strength and price. As with anything else, moderation is also key.
The plants are listed alphabetically.
 Individual herbs
- Aconite (Aconitum spp. also known as Wolfsbane, or Monkshood)
- Used in traditional Chinese medicine for rheumatism, bruises, arthritis, acute hypothermia, diarrhea, impotence, and yang imbalance. There isn't enough evidence to know if it's good for anything.
- Aconite is very poisonous, and ingestion may lead to nausea, vomiting, weakness, sweating, breathing problems, heart problems, and death. Topical use can also cause severe side effects.
- Aloe (Aloe vera)
- It is effective for topical application to treat minor burns and some skin problems, but may possibly be too dangerous to use internally as a laxative for constipation. Aloe was formerly promoted by some CAM practitioners as a cancer treatment, but it is ineffective, and some patients died after receiving aloe injections.
- American skullcap (Scutellaria lateriflora)
- Claimed to be good for tension, anxiety, insomnia, neurasthenia, panic, headaches, fatigue, depression, melancholy, convulsions, jerking muscles, epilepsy, wobbliness, heart trembles, depression, arthritis, fever, snake bites, and rabies. Claimed to be good for PMS when used with chaste tree or false unicorn root.
- Not much research has been done on the herb, so these claims can't be evaluated.
- High doses can cause giddiness, stupor, mental confusion, twitching, irregular heartbeat, and seizures. American skullcap has, on occasion, been contaminated with germander, which can cause liver damage. American skullcap has been implicated in some cases of liver damage.
- Arnica (Arnica montana, also known as "Leopard's Bane" or "Dog's Bane")
- Used for skin problems, but is not effective.
- Topical arnica is generally safe, but "repeated use can cause skin reactions, severe inflammation, itching, blisters, skin ulcers, and other allergy-related skin problems." Arnica can cause irritation when used on broken skin.
- Arnica is extremely toxic and shouldn't be taken internally.
- Asian ginseng[wp] (Panax ginseng)
- The oriental wonder plant. Cures everything from feeling tired to being dead for a hundred years. Ginseng is effective for improving thinking skills, erectile dysfunction, and chronic obstructive pulmonary disease symptoms. A specific cream containing ginseng can help with premature ejaculation.
- Side effects may include insomnia, or, more rarely, menstrual problems, breast pain, increased heart rate, high or low blood pressure, headache, loss of appetite, diarrhea, itching, rash, dizziness, mood changes, vaginal bleeding, Stevens-Johnson syndrome (a severe rash), liver damage, severe allergic reactions, mania and psychosis. Panax ginseng contains a substance that has been found to cause birth defects in animals.
- Bilberry (Vaccinium spp.)
- Birthwort (Aristolochia spp.)
- Used in Traditional Chinese Medicine (for various things, including eczema) and Ayurveda. It contains aristolochic acid,[wp] (AA) which is a known carcinogen, and causes kidney failure and upper urinary tract cancer. Birthwort is considered to be a significant cause of kidney failure and upper urinary tract cancer in Taiwan, because of the popularity of herbal medicine there (approximately 33% of Taiwan's herbal medicine prescriptions contain aristolochic acid, and AA has been ingested by approximately 33% of Taiwan's population.) In Switzerland, a weight loss spa using TCM herbs gave its clients herbal supplements containing birthwort, and as a result, 105 out of 1800 of its patients developed kidney failure, and several also developed upper urinary tract cancer.
- European birthwort (Aristolochia clematitis) was also used as a medicinal plant and contains aristolochic acid. It has been linked to thousands of cases of kidney failure (Balkan endemic nephropathy[wp]) in Bosnia and Herzegovina, Bulgaria, Croatia, Romania and Serbia.
- Tl;dr: May cause cancer and kidney failure. Don't take it.
- Bitter orange (Citrus × aurantium)
- Black walnut (Juglans nigra)
- Claimed to be good for killing parasites (such as worms), and treating acne, thyroid disease, colitis, eczema, hemorrhoids, ringworm, sore throats, tonsillitis, skin irritations, wounds, and curing cancer. Unfortunately, there is absolutely no evidence to support any of these assertions. There is insufficient research to determine what side effects it has or whether it is effective for anything.
- Betelnut (Areca catechu nuts, wrapped and eaten with Piper betel leaves)
- A flushed face with mild euphoria which lasts a few minutes but the bitterness offsets the benefits. Used in traditional Chinese medicine for deworming and in SE Asia to colour teeth. It's also apparently "widely used in Ayurveda".
- Prolonged use can lead to mouth, liver, cervical, stomach, prostate, lung, and sweat gland cancer. Other side effects of betel nut/leaf include skin color changes, dilated pupils, blurred vision, wheezing/difficulty breathing, increased breathing rate, salivation, increased tearing, incontinence, sweating, diarrhea, fever, confusion, problems with eye movement, psychosis, amnesia, stimulant effects, and a feeling of euphoria. It can also cause dependence, and withdrawal can cause anxiety or memory lapse. Betel nut chewing can cause nausea, vomiting, diarrhea, stomach cramps, chest pain, irregular heartbeats, high or low blood pressure, and irregular heart beats.
- Black cohosh (Actaea racemosa)
- Side effects may include stomach upset, cramping, headache, rash, a feeling of heaviness, vaginal spotting or bleeding, and weight gain.
- Cat's claw (Uncaria tomentosa or Uncaria guianensis)
- A claimed cure-all for HIV, cancer, you name it, and as usual it's a load of hogwash. It may have an unwanted effect on blood pressure.
- Greater Celandine (Chelidonium majus)
- Used internally for sedation, gallstone prevention, intestinal and digestive problems, liver disease, and eye irritation, and topically for ringworm, warts, and corns. Also, "liver diseases; has been used for inflammation of the gallbladder, inflammation of the bilary duct, loss of appetite, jaundice, hepatitis, dropsy, gout, arthritis, rheumatism, fevers, spasmodic coughs, bronchitis, asthma, intestinal polyps, breast lumps, angina, cramps, arteriosclerosis, gout, water retention, skin eruptions, scurvy, ulcers, cancers (specifically skin and stomach). [...] The tincture has been used for liver problems, facial, head, and shoulder neuralgia, constipation."
- There is no evidence to support any of the above claims. However, a specific herbal mixture, which contains celandine along with several other herbs, may be effective for dyspepsia.
- May cause hepatitis. (And it's claimed to be good for liver problems...)
- Lesser Celandine (Ranunculus ficaria)
- A buttercup-like plant unrelated to the Greater Celandine, one of the poppy family; traditionally used to treat piles; rare cases of hepatitis after use.
- Chamomile (Chrysanthemum spp.) See Roman chamomile
- Chaparral (Larrea divaricata coville)
- Used for lots of things, including cancer. Chaparral is not effective for cancer and not known to be effective for anything else, either. One CAM site claims it's good for lots of unrelated illnesses and only has "temporary unpleasant side effects", but it's actually very dangerous.
- Can cause fatal liver damage and kidney failure. Other side effects may include fatigue, stomach pain, diarrhea, weight loss, fever, itching, rash, and allergic reactions. Despite the title of that old cowboy serial, Chaparral cannot get you high.
- Chrysanthemum (Asteraceae spp.)
- Cinnamon (Cinnamomum spp.)
- Most of the spice sold in the U.S. as culinary cinnamon is from the species Cinnamonium cassia, a.k.a. Chinese cinnamon.
- Claims: Lowers LDL cholestrol, maintains blood sugar, promotes appetite for elderly and sick, antioxidant, anti-microbial, anti-bacterial, stops tumor growth, anti inflammatory, arthritis, hair loss and bladder infections, colds, upset stomach, and even pimples.
- Truth: Apparently, it really does stop tumor growth - when it is injected into tumors in mice. Clearly, it's not really a home remedy. The indications are quite good that it has an effect on blood sugar, however the details remain unknown. None of the other claims seem to hold up, however.
- Cloves (Syzygium aromaticum)
- Used as an anesthetic in dentistry. Generally safe.
- However, large amounts of cloves or clove oil may cause nausea, vomiting, abdominal pain, diarrhea, burns in the mouth and throat, sore throat, seizures, difficulty breathing, rapid heartbeat, sleepiness, intestinal bleeding, and liver or kidney failure. More serious side effects may occur in children, even when small amounts are used. "Excessive application of undiluted clove oil on or near the teeth may cause irritation or damage to the gums or mouth and may damage the dental pulp, the soft core of the tooth, made up of living soft tissue and cells. [...] Undiluted clove oil may cause skin irritation, rashes, or even burns. Clove oil can cause blindness in laboratory animals, so keep clove preparations away from the eyes."
- Coca leaves (Erythroxylon coca)
- Used for
nasal congestion in powdered formpain relief in the Andes. Otherwise known as cocaine when refined. Side effects include turning into a yuppie, or a celebrity.
- Not to be confused with cocoa or coconuts.
- Used for
- Coltsfoot (Tussilago farfara)
- Not enough research has been done to evaluate efficacy. Used as an expectorant and for coughs. Coltsfoot cigarettes are used for asthma.
- Can cause liver damage and cancer. Coltsfoot supplements that are labeled "PA-free" (meaning without pyrrolizidine alkaloids) are better, but their safety is unknown.
- Comfrey (Symphytum officinale)
- Used internally for stomach problems and topically for wounds, though its effectiveness for these uses has not been studied.
- Can cause liver damage leading to death. Comfrey contains compounds called pyrrolizidine alkaloids, which have been shown by animal studies to cause liver tumours, so the plant may also cause cancer. Even topical use may lead to a dangerous build-up in the body of some of the herb's poisonous substances, so long-term use is not advised.
- Country mallow (Sida cordifolia)
- Not enough research to evaluate efficacy. Used in Ayurvedic medicine.
- Country mallow contains ephedrine, which is also found in ephedra, and may cause ephedrine-related side effects like high blood pressure, heart attacks, muscle disorders, seizures, strokes, irregular heartbeat, loss of consciousness, and death. Other side effects may include dizziness, restlessness, irritability, insomnia, headache, lack of appetite, nausea, vomiting, flushing, tingling, difficulty urinating, kidney stones, and pounding heartbeat. May make anxiety, thyroid problems, and angina worse.
- Dandelion (Taraxacum spp)
- Known to be an effective diuretic, claimed to help with digestive and liver problems, but there has been no serious research of these claimed effects. The entire plant is edible.
- The plant has no harmful side effects aside from its diuretic properties, which may interfere with certain medications, and or cause increased frequency of changing pajamas and bedsheets.
- Effective for osteoarthritis pain. Insufficient study has been done to evaluate its effectiveness for anything else.
- Side effects may include diarrhea, nausea, vomiting, abdominal pain, headaches, ringing in the ears, loss of appetite, and loss of taste. Other side effects may include allergic skin reactions, menstrual problems, and changes in blood pressure. Use of devil's claw during pregnancy is not advised, as it may harm the fetus.
- Dong quai (Angelica sinensis)
- Used in traditional Chinese medicine.
- It may be dangerous to take dong quai in large amounts for a long time because it contains carcinogens. Dong quai can cause skin to be more sensitive to sunlight, thus possibly increasing the risk of skin cancer. It may or may not act like estrogen in the body. It can slow blood clotting and increase the risk of bleeding, and so should not be taken less than 2 weeks before surgery. Dong quai may increase the risk of miscarriage.
- Echinacea (Echinacea spp.)
- Eleuthero (Eleutherococcus senticosus)
- Like many other herbs, eleuthero is promoted for a wide variety of unrelated conditions. There is no evidence to support its effectiveness in treating anything.
- Side effects may include headache, diarrhea, nervousness, trouble sleeping, raised blood pressure and increased heart rate. However, it may also lower blood sugar levels. "Eleuthero may alter the amount of time it takes for bleeding to stop."
- Ephedra (Ephedra sinica, also known as ma huang)
- Used in traditional Chinese medicine for promoting sweating and the treatment of upper respiratory tract infections during winter. Studies done on the active chemicals of Ephedra/ma juang demonstrates that it speeds the metabolism, thus, the reason for its use and abuse as a performance-enhancing drug by athletes and for weight loss.
- Side effects may include dizziness, restlessness, anxiety, irritability, heart pounding, headache, loss of appetite, nausea, vomiting, hypertension, insomnia, arrhythmia, nervousness, tremor, seizure, cerebrovascular event, myocardial infarction, kidney stones, high blood pressure, heart attacks, muscle disorders, seizures, strokes, irregular heartbeat, loss of consciousness, death, and others.
- Dietary supplements containing ephedra are banned in the U.S. because they pose "an unreasonable risk to health."
- European birthwort (Aristolochia clematitis) See Birthwort
- Evening primrose oil (Oenothera spp.)
- Eyebright (Euphrasia spp.)
- Used for eye problems.
- Side effects may include confusion, headache, tearing, itching, redness, vision problems, sneezing, nausea, toothache, constipation, cough, trouble breathing, trouble sleeping (insomnia), sweating, and others.
- Effective mild painkiller. MedlinePlus Supplements notes that "Some feverfew tablet products can contain little or no feverfew."
- Side effects may include upset stomach, heartburn, diarrhea, constipation, bloating, flatulence, nausea, and vomiting. Other reported side effects include nervousness, dizziness, headache, trouble sleeping, joint stiffness, tiredness, menstrual changes, rash, pounding heart, and weight gain. Chewing raw feverfew may lead to mouth ulcers, loss of taste, and swelling of the lips, tongue, and mouth.
- Fennel (Foeniculum vulgare)
- Not enough research done to evaluate claims.
- Foxgloves (Digitalis spp.)
- Used for heart problems. Is effective, but:
- Whether or not a given quantity of digitalis contains enough digoxin to lead to an overdose depends on the individual plant(s) it's from (each individual plant (even in the same species) has a different digoxin content) so those using digitalis are effectively playing Russian roulette. There is no way of knowing if one pill is good, or if it will lead to an overdose and kill you. As Encyclopedia.com puts it:
Foxglove is no longer used as a heart medicine because the therapeutic dose and the lethal dose are very close. Seasonal variations in the level of cardiac glycosides in the plant make the safe dose impossible to estimate except by an experienced physician and prescriber of the herb who monitors the patient on an hourly basis for signs of overdose. Few living doctors and herbalists can safely use digitalis as a plant extract. Specific standardized doses of pharmaceutical digoxin are used instead.
- The solution is to use pure digoxin, if prescribed by a doctor, because the doses are exactly measured.
- Side effects may include irregular heart function and death. Symptoms of digitalis overdose may include "stomach upset, small eye pupils, blurred vision, strong slow pulse, nausea, vomiting, dizziness, excessive urination, fatigue, muscle weakness and tremors, stupor, confusion, convulsions, abnormal heartbeats, and death. Long-term use of digitalis can lead to symptoms of toxicity, including visual halos, yellow-green vision, and stomach upset."
- Garlic[wp] (Allium sativum)
- Claims: Fights minor viral infections such as cold and sore throat, lowers blood sugar and blood pressure, reduces risk of certain cancers.
- Truth: Known antimicrobial effect in vitro, tests suggest some effect on throat infections in greater-than-typical amounts. Cancer claims based on large-scale statistics of incidence and diet, probably bullshit. Blood sugar and blood pressure claims indeterminate. Seductive effect on body odor well-documented and conclusive. Freshens breath for up to twelve hours.
- Side effects may include: bad breath, a burning sensation in the mouth or stomach, heartburn, gas, nausea, vomiting, body odor, diarrhea, and an increased risk of bleeding. "Asthma has been reported in people working with garlic, and other allergic reactions are possible."
- Germander (Teucrium spp.)
- Claimed to be effective for gout, fever, diarrhea, gallbladder problems, and claimed to be useful for weight loss and as an antiseptic. There is currently insufficient evidence to evaluate these claims.
- May cause hepatitis, cirrhosis, and death. A weight loss supplement sold in France that contained germander caused several cases of hepatitis, and because of this, the herb is banned in that country and others.
- Ginseng[wp] (panax spp.) See Asian ginseng or Dong quai (female ginseng)
- Grapefruit seed extract (Citrus × paradisi)
- Grape seed extract (Vitis vinifera)
- Used for weight loss.
- Side effects may include stomach upset and constipation, and, in rare cases, liver damage. Caffeine-related side effects may include headache, nervousness, sleep problems, vomiting, diarrhea, irritability, irregular heartbeat, tremor, heartburn, dizziness, ringing in the ears, convulsions, confusion, and reduced absorption of iron from food. Also implicated in outbreaks of Britishness. Jolly splendid, indeed!
- Groundsel (Senecio vulgaris)
- Claimed to be an "Anthelmintic; Antiscorbutic; Diaphoretic; Diuretic; Emmenagogue; [...] Poultice; Purgative", and claimed to be good for stomach problems and worms. There is not enough evidence to evaluate these claims.
- Groundsel is very toxic, and can cause liver damage, cancer, and birth defects. It should not be used.
- Goldenseal[wp] (Hydrastis canadensis)
- Used for "immune system boosting". The evidence doesn't suggest Goldenseal is effective for any condition.
- Small doses are fine, except during pregnancy or breastfeeding, since goldenseal might cause brain damage to the baby. "High doses may cause breathing problems, paralysis, and even death. Long-term use may lead to vitamin B deficiency, hallucinations, and delirium." It may also affect blood pressure unpredictably because it contains several different compounds that have opposite effects on blood pressure. It can also make you more sensitive to light.
- Henbane (Hyoscyamus niger)
- Used for pain, Parkinson's disease symptoms, and ulcers. It is also smoked to "cure" asthma and bronchitis (sounds familiar). There is no evidence to support its use for any of these conditions.
- Henbane is toxic, and when used for self-treatment may result in fatal poisoning.
- Side effects may include dry mouth, red skin, constipation, overheating, reduced sweating, vision disturbances, increased heart rate, urination problems, drowsiness, restlessness, hallucinations, delirium, manic episodes, and death. Mostly death.
- For a while, henbane berries were used in the manufacture of an herbal beer flavoring called "gruit," which was flavored with various sweet and bitter herbs, before people began using hops. Fell out of favor during the Middle Ages when the Reinheitsgebot declared that all beers in the Holy Roman Empire could only be made with barely, hops, water, and yeast.
- Horny goat weed (Epimedium spp.)
- Horse chestnut (Aesculus hippocastanum)
- Standardized horse chestnut seed extract is good for varicose veins, chronic venous insufficiency, and symptoms of poor blood circulation.
- Standardized, esculin-free horse chestnut seed extract is mostly safe, with side effects including dizziness, headache, stomach upset, and itching. It may lower blood sugar. Raw horse chestnut seed, leaf, bark, and flower, on the other hand, are toxic and can be lethal.
- Horsetail (Equisetum sp.)
- Insufficient research done on efficacy.
- Side effects of long-term use may include thiamine deficiency (beriberi), low potassium levels, and (in diabetics) low blood sugar. Horsetail contains chromium and may increase the risk of chromium poisoning if taken with chromium-containing herbs like bilberry, brewer's yeast, or cascara.
Symptoms of beriberi may include difficulty walking, loss of feeling (sensation) in hands and feet, loss of muscle function or paralysis of the lower legs, mental confusion/speech difficulties, pain, strange eye movements (nystagmus), tingling, vomiting, awakening at night short of breath, increased heart rate, shortness of breath with activity, and swelling of the lower legs. Beriberi, if caught early enough, can usually be reversed, but possible complications of beriberi may include coma, congestive heart failure, psychosis, and death. Because of the possibility of thiamine deficiency, people consuming horsetail should take thiamine supplements.
- Impila (Callilepsis laureola)
- Jimson weed (Datura stramonium)
- Insufficient evidence to evaluate efficacy. Jimson weed leaves are smoked for asthma.
- Jimson weed is poisonous and can cause dry mouth and extreme thirst, vision problems, nausea and vomiting, fast heart rate, hallucinations, high temperature, seizures, confusion, loss of consciousness, breathing problems, and death. "The deadly dose for adults is 15-100 grams of leaf or 15-25 grams of the seeds."
- Kava (Piper methysticum)
- Effective for anxiety.
- Side effects may include liver damage leading to death, even with short-term use (1-3 months) of normal doses, and aedation, oral and lingual dyskinesia, torticollis, oculogyric crisis, exacerbation of Parkinson's disease, painful twisting movements of the trunk, and rash.
- Licorice (Glycyrrhiza glabra)
The University of Maryland Medical Center lists a large number of possible medicinal uses of the licorice plant, saying licorice "has been used in both Eastern and Western medicine to treat a variety of illnesses...It acts as a demulcent, a soothing, coating agent, and as an expectorant, meaning it helps get rid of phlegm."
- It has side effects in large quantities: Bad for heart disease, kidney disease, pregnant women, male sexual function, among others, and there are many other side effects. Taking a lot of licorice can cause brain damage even in healthy people.
- Side effects may include include tiredness, absence of a menstrual period in women, headache, water and sodium retention, decreased sexual interest and function in men, miscarriages or early deliveries, and raised blood pressure. It can also make heart and kidney disease worse.
- According to MedlinePlus Supplements, "Consuming 30 grams or more of licorice daily for several weeks can cause severe side effects including high blood pressure, low potassium in the blood, weakness, paralysis, and occasionally brain damage in otherwise healthy people. In people who eat a lot of salt or have heart disease, kidney disease, or high blood pressure, as little as 5 grams per day can cause these problems." Licorice "might act like estrogen in the body. If you have any condition [such as breast cancer, uterine cancer, ovarian cancer, endometriosis, or uterine fibroids] that might be made worse by exposure to estrogen, don’t use licorice." Licorice can interact with grapefruit juice, possibly increasing its ability to deplete human potassium levels, and licorice's side effects of sodium and water retention and increase in blood pressure can worsen if taken with salt.
- Licorice can interact with heart medicines, steroids, diuretics, or insulin.
- Lily-of-the-valley (Convallaria majalis)
- Used for epileptic seizures, strokes, angina, conjunctivitis, leprosy, and heart problems. Not enough study has been done to evaluate any of the claims.
- The plant is poisonous and can be fatal. Doses must be very specific and prescribed by a professional (although what with the lack of evidence, what's the point?) Self-medication or wrong doses may result in blurred vision, excessive urination at night, halos around objects, diarrhea, Loss of appetite, Stomach pain, Vomiting or nausea, irregular or slow heartbeat confusion, depression, disorientation, drowsiness, fainting, headache, lethargy, weakness, rash, and hives.
- Lobelia (Lobelia inflata)
- Used for asthma, bronchitis, cough, and smoking cessation. Not enough study has been done to verify lobelia's effectiveness for any of these.
- Side effects may include profuse sweating, nausea, vomiting, diarrhea, tremors, rapid heartbeat, mental confusion, convulsions, hypothermia, coma, and death. It's not called Indian Tobacco for nothing.
- Ma huang: See Ephedra.
- Madder root (Rubia tinctorum)
- Sometimes used in herbal medicine as an "astringent diuretic, emmenagogue", and claimed to be good for many conditions, including alkaline urine, diarrhea, inflammation, wounds, broken bones, fever, and many others. There is no evidence to support the use of madder root for any of these conditions. The root is used in Ayurveda and Hildegard medicine. Madder root is also used for dyeing fabrics.
- May cause cancer, birth defects, and miscarriages. It can also make urine, saliva, perspiration, tears, and breast milk turn red. One wonders if happier root would be any better.
- Marijuana (Cannabis spp.)
- Effects may include mild euphoria, relaxed muscles, increased appetite and...wait, what? Did I say that out loud? Whoa... Have you ever looked at your hand? I mean REALLY looked at your hand? side effects include paranoia and apathy. Marijuana and other cannabis products have little or no 'healing' purposes, but may relief symptoms of other conditions or diseases. It is considered one of the safest substances of abuse known to men, including legal drugs, such as alcohol and coffee.
- Mate (Ilex paraguariensis)
- Consumed as a beverage.
- Non-caffeine-related side effects include an increased risk of mouth, esophageal, laryngeal, kidney, bladder, and lung cancer. Caffeine-related ones include insomnia, nervousness and restlessness, stomach upset, nausea and vomiting, increased heart rate and breathing, high blood pressure, headache, ringing in the ears, irregular heartbeats, slowed blood clotting, and worsened diarrhea.
- Best remove it from your diet.
- Milk thistle (Silybum marianum)
- Mistletoe (Viscum album)
- Claimed to be good for cancer prevention, hypertension, and insomnia. Mistletoe isn't effective for cancer; insufficient research has been done to evaluate the other claims.
- When small amounts are taken, it is safe, with mild side effects of headaches, fever, and chills. Large amounts are toxic and can be fatal; symptoms may include seizures, coma, death, blurred vision, nausea and vomiting, stomach pain, diarrhea, slow or irregular heartbeat, low blood pressure, confusion, and drowsiness.
- Mu Tong (Caulis aristolochiae)
- Neem (Azadirachta indica)
- Not known to be effective for anything.
- Safe when taken short-term by adults. Neem is contraindicated for children, because it can cause vomiting, diarrhea, drowsiness, blood disorders, seizures, loss of consciousness, coma, brain disorders, and death. High-dose or long-term internal use by adults is dangerous, and can harm the kidneys and liver, lower blood sugar, and cause infertility and miscarriages.
- Oil of oregano
- A herbal supplement often vaunted as an anti-fungal, anti-viral, anti-bacterial, abortifactant, anti-asthma, anti-malaria, antioxidant and anti-cold/flu/headache medication (take your pick). While it has a higher rate of success on malaria and bacteria on the skin than normal water, it has significantly less sucess than any standard over-the-counter antibiotic or medicinal anti-malaria drug. As with most woo, there is always a glint of truth that gets warped into $$$$$. It is a good antioxidant, but not more so than raw oregano, which tastes better and makes wicked salads. And, despite its name, it tastes absolutely foul (as this user will attest).
- Side effects may include gastrointestinal issues and allergic reactions.
- Oleander (Nerium oleander)
- Insufficient research to evaluate efficacy. Used for muscle cramps, asthma, cancer, and AIDS.
- Oleander leaf is poisonous, and can cause fatal heart failure. Symptoms may include nausea, vomiting, colic, appetite loss, dizziness, drowsiness, high potassium levels, dilated pupils, bloody diarrhea, seizures, loss of consciousness, slow or irregular pulse, and heart block. Oleander seeds are also toxic, as is the rest of the plant, sap, twigs, roots, etc.
- Parsley (Petroselinum crispum)
- Sometimes used for home abortions, but its effectiveness for this has not been scientifically studied.
- The claims: Parsley is touted as a general anti-toxin, control blood pressure, cure diabetes, urinary tract infections, prevents cancer, stimulates contractions of the uterus, cures rheumatism, treats kidney and bladder stones, and can even remove tooth aches.
- The truth: Surprisingly, it is dangerous for women, as it can cause the uterus to contract prematurely and should not be inserted into or rubbed near the uterus. It is also helpful for treating cancer patients, as it contains high levels of apiginin, which prevent blood from reaching the tumor. And it has mild anti microbial-use - on those days when you can't run to your medicine cabinet and grab a tube of far more effective antibiotic.
- It is harmless when taken in the small amounts found in food, but the large amounts used in herbal medicine may cause anemia and liver or kidney problems, and make water retention, high blood pressure, and kidney disease worse. Topically applied parsley oil can make skin become more sensitive to sunlight and cause a rash.
- Pennyroyal[wp] (Lamiaceae)
- Used in various ways, such as for inducing miscarriages and deworming. There is no evidence to support the effectiveness of pennyroyal for anything besides abortions (but see note below).
- The essential oil is toxic and can be fatal if ingested.
- Peppermint oil (Mentha piperita)
- Primrose oil: See Evening primrose oil.
- Roman chamomile (Chamaemelum nobile)
- Sassafras (Lauraceae spp.)
- Claimed to be effective for joint pain and preventing colds and flus. There is no evidence to support its use for these conditions.
- Sassafras is poisonous, and even 5ml can be fatal. Side effects may include cancer, liver damage and miscarriages. Also, sweating and hot flashes. "High amounts can cause vomiting, high blood pressure, hallucinations, and more severe side effects. It can cause skin rashes when used on the skin."
- Saw palmetto (Serenoa repens)
- Extract of the fruit of a fan palm. Taken for BPH (benign prostatic hyperplasia) a.k.a. Getting up 5 times at night to piss. Some studies assert its effectiveness.
- Senna (Cassia angustifolia)
- Effective for constipation.
- Short-term use may cause stomach discomfort, cramps, and diarrhea. Long-term use (over two weeks) can stop the bowels from functioning properly and cause dependence; it may also cause heart function disorders, muscle weakness, liver damage, and other side effects.
- Siberian ginseng (Eleutherococcus senticosus) See Eleuthero
- Soursop (Annona muricata)
- Skullcap: See American skullcap, Chinese skullcap. European skullcap is used there as a substitute for American skullcap, and has similar ingredients.
- Spinach (Spinacia oleracea)
- May contribute to kidney stone formation by increasing the amount of oxolate in the urine.
- Squill (Urginea maritime)
- Not enough research to evaluate efficacy for anything. Used for heart problems, bronchitis, asthma, whooping cough, and wounds.
- The herb is cardiotoxic and can be lethal, with side effects including stomach irritation, loss of appetite, diarrhea, vomiting, headache, vision changes, depression, confusion, hallucinations, irregular heartbeat, skin rash, miscarriages, seizures, life-threatening abnormal heart rhythms, and death.
- Stevia (Asteraceae spp.)
- Used as a sweetener.
- Usually no side effects, but rare ones may include bloating, nausea, dizziness, muscle pain, and numbness.
- St. John's wort (Hypericum perforatum)
- Regarded by herbalists as an effective treatment for depression (even though it isn't). May interfere with effectiveness of other drugs.
- St John's wort may cause cataracts in people exposed to visible or ultraviolet light after taking it. Other side effects may include gastrointestinal disturbances, allergic reactions, fatigue, dizziness, confusion, dry mouth, photosensitivity, mania and psychosis
- Used topically (and is effective) for fungal infections, acne, and athlete's foot. Tea tree oil is, however, less effective than medications for curing athlete's foot.
- Side effects may include skin irritation and swelling, and "in people with acne, it can sometimes cause skin dryness, itching, stinging, burning, and redness." Applying products containing both tea tree and lavender oil to prepubescent boys may cause gynecomastia (larger breasts). Tea tree oil is highly toxic when ingested, even in small quantities, so it should never be taken by mouth.
- Tobacco (Nicotiana spp.)
- 'Nuff said.
- Valerian (Valeriana officinalis)
- Willow bark (Salix spp.)
- Used for pain relief (and is effective, obviously).
- Side effects may include: stomach upset, digestive system upset, itching, an increased risk of children developing Reyes syndrome, ulcers, stomach bleeding, and liver toxicity. (No better than aspirin, then.) Side effects from overdosing may include skin rash, stomach inflammation/irritation, nausea, vomiting, kidney inflammation, and tinnitus (ringing in the ears). Willow bark can be anywhere from 0.08% to 12.6% salicin (the active ingredient).
- Wintergreen (Gaultheria procumbens)
- Insufficient research to evaluate efficacy. Used for asthma, rheumatism, and headache.
- Wintergreen is safe, but internally taken wintegreen oil is toxic and can cause ringing in the ears, nausea, vomiting, diarrhea, headache, stomach pain, confusion, and death. (Wintergreen oil contains methyl salicylate, and 5 mL of the oil is equivalent to about 21.5 aspirin tablets.) Topical use can cause skin irritation.
- In addition to producing a blue dye, woad has alleged medicinal uses. Chemicals from woad might be used to prevent cancer, as woad can produce high levels of glucobrassicin. Young leaves when damaged can produce more glucobrassicin, up to 65 times as much.
- Indigo woad Root is a traditional Chinese medicine herb that comes from the roots of woad, but often incorrectly listed under the synonymic name, Isatis indigotica. It is also known as Radix isatidis. The herb is cultivated in various regions of northern China. The roots are harvested during the autumn and dried. The dried root is then processed into granules, which are most commonly consumed dissolved in hot water or tea. The product, called Banlangen Keli, is very popular throughout China, and used to remove toxic heat, soothe sore throat and to treat influenza, measles, mumps, syphilis, or scarlet fever. It is also used for pharyngitis, laryngitis, erysipelas, and carbuncle, and to prevent hepatitis A, epidemic meningitis, cancer and inflammation.
- Possible minor side effects include allergic reactions and dizziness; only large dosages or long term usage can be toxic to the kidneys.
- Wormwood (Artemisia absinthium)
- Yerba mate: See Mate
 Multi-herb mixtures
This list is mainly for TCM remedies that consist of multiple plants.
- Fo ti: See he shou wu
- He shou wu
- Jin bu huan
- Used as a sedative and analgesic, and for asthma, bronchitis, night blindness, delirium, epilepsy, vertigo, fever and inflammation. The herbs used vary, but can include Lycopodium serratum, Panax, Pseudo ginseng, Polygala chinensis and two species of Stephania.
- May cause hepatitis. It is sometimes contaminated with lead.
- Long dan xie gan wan: See Xie gan wan
- Xie gan wan (also known as Long dan xie gan wan)
- Used for acne, among other things. It contains birthwort and can cause kidney failure and cancer.
These treatments have not generally been evaluated clinically.
 See also
- Herbal supplements
- Cansema (black salve)
- Naturalistic fallacy
- Nature woo
- Appeal to tradition
- Placebo effect
- The Poison Garden (a site dedicated to poisonous plants)
- ↑ There are without a doubt many traditional remedies whose (possibly serious) adverse effects are completely unknown. It's interesting to note that traditional medicine can use carcinogenic and hepatotoxic plants for millenia without detecting their side effects. If a herb really is good for something, the beneficial compounds can be used as drugs, while leaving the toxic ones behind; thus the patient gets the benefits of the herb without the unnecessary risks.
- ↑ Aconite, altMD.
- ↑ ACONITE, WebMD.
- ↑ 4.0 4.1 ACONITE, WebMD.
- ↑ 5.0 5.1 Aloe, Cancer.org.
- ↑ Skullcap, Herbs2000.com.
- ↑ 7.0 7.1 7.2 Skullcap, University of Maryland Medical Center.
- ↑ Skullcap, LiverTox.com.
- ↑ 9.0 9.1 9.2 Arnica, Cancer.org.
- ↑ Not really, but some of the claims...
- ↑ 11.0 11.1 11.2 11.3 Ginseng, WebMD.
- ↑ 12.0 12.1 Mania and Psychosis Associated with St. John's Wort and Ginseng
- ↑ Bilberry : Science and Safety | NCCAM
- ↑ bilberries at WebMD
- ↑ Aristolochic Acid: FDA Concerned About Botanical Products, Including Dietary Supplements, Containing Aristolochic Acid, FDA, May 31, 2000.
- ↑ 16.0 16.1 16.2 Chung-Hsin Chena, et al. "Aristolochic acid-associated urothelial cancer in Taiwan." Proceedings of the National Academy of Sciences. 2012 April 9.
- ↑ "Study blames herb for high cancer rate." Taipei Times. 2012 April 11.
- ↑ Aristolochia clematitis, ThePoisonGarden.
- ↑ 19.0 19.1 BITTER ORANGE, WebMD.
- ↑ But then, what herb isn't claimed to cure cancer?
- ↑ Black walnut, Cancer.org.
- ↑ Chinese Herbs A to E
- ↑ 
- ↑ 24.0 24.1 24.2 24.3 Betel nut (Areca catechu L.), Wellness.com.
- ↑ Betel Nut, InteliHealth.
- ↑ "IARC Monographs Programme finds betel-quid and areca-nut chewing carcinogenic to humans." World Health Organization. 2003 August 7.
- ↑ Jenny Chou. "Chewing betel nuts now a serious matter: DOH." Taipei Times. 2005 December 6.
- ↑ BLACK COHOSH, WebMD.
- ↑ 29.0 29.1 29.2 Celandine, Cancer.org.
- ↑ 30.0 30.1 30.2 30.3 GREATER CELANDINE, WebMD.
- ↑ Celandine - Herb Database + Images
- ↑ Necrotizing hepatitis after taking herbal remedies at Pubmed.
- ↑ 33.0 33.1 Chaparral, Nature's Detergent
- ↑ 34.0 34.1 34.2 Chaparral, Cancer.org.
- ↑ 35.0 35.1 CHRYSANTHEMUM, WebMD.
- ↑ This is a reference of the claim to cure, please don't try these recipes.
- ↑ http://findarticles.com/p/articles/mi_6801/is_2_21/ai_n32462270/
- ↑ Pubmed
- ↑ 39.0 39.1 39.2 Cloves, Cancer.org
- ↑ COLTSFOOT, WebMD.
- ↑ Coltsfoot, Herbs2000.com.
- ↑ COLTSFOOT, WebMD.
- ↑ 43.0 43.1 "Comfrey." American Cancer Society.
- ↑ 44.0 44.1 "Comfrey." University of Maryland Medical Center.
- ↑ 45.0 45.1 45.2 COUNTRY MALLOW, WebMD.
- ↑ Bala Leaf Certified Organic (Sida cordifolia) Powder Bulk
- ↑ 12 Supplements You Should Avoid
- ↑ http://www.nlm.nih.gov/medlineplus/druginfo/natural/706.html
- ↑ 49.0 49.1 49.2 49.3 49.4 Devil's claw: MedlinePlus Supplements.
- ↑ 50.0 50.1 50.2 DONG QUAI, WebMD.
- ↑ 51.0 51.1 Dong Quai (Angelica sinensis), Mayo Clinic.
- ↑ 52.0 52.1 Echinacea, Cancer.org.
- ↑ 53.0 53.1 Eleuthero (formerly Siberian Ginseng), Cancer.org.
- ↑ 54.0 54.1 Ephedra, WebMD.
- ↑ 55.0 55.1 55.2 Herbal Remedies: Adverse Effects and Drug Interactions, MELANIE JOHNS CUPP. Am Fam Physician. 1999 Mar 1;59(5)1239-1244.
- ↑ FDA Acts to Remove Ephedra-Containing Dietary Supplements From Market, November 23, 2004.
- ↑ Oral evening primrose oil and borage oil for eczema, Bamford JT, Ray S, Musekiwa A, van Gool C, Humphreys R, Ernst E, Cochrane Database Syst Rev. 2013 Apr 30;4:CD004416. doi: 10.1002/14651858.CD004416.pub2.
- ↑ 58.0 58.1 Evening primrose oil, WebMD.
- ↑ Eyebright, WebMD.
- ↑ 60.0 60.1 Feverfew, MedlinePlus Supplements.
- ↑ Feverfew, University of Maryland Medical Center.
- ↑ FENNEL, WebMD.
- ↑ Foxglove, Encyclopedia.com.
- ↑ 64.0 64.1 Digitalis, WebMD.
- ↑ 65.0 65.1 Garlic, WebMD. Accessed on the 15th of December, 2012.
- ↑ 66.0 66.1 GERMANDER, WebMD.
- ↑ Germander, LiverTox.
- ↑ Aspects of the antimicrobial efficacy of grapefruit seed extract and its relation to preservative substances contained, von Woedtke T, Schlüter B, Pflegel P, Lindequist U, Jülich WD, Pharmazie. 1999 Jun;54(6):452-6.
- ↑ Identification of benzethonium chloride in commercial grapefruit seed extracts, Takeoka G, Dao L, Wong RY, Lundin R, Mahoney N, J Agric Food Chem. 2001 Jul;49(7):3316-20.
- ↑ Simultaneous identification and quantification by liquid chromatography of benzethonium chloride, methyl paraben and triclosan in commercial products labeled as grapefruit seed extract, Avula B, Dentali S, Khan IA, Pharmazie. 2007 Aug;62(8):593-6.
- ↑ Grape seed, University of Maryland Medical Center.
- ↑ Grape Seed Extract: Benefits and Side Effects, WebMD.
- ↑ 73.0 73.1 Green Tea, WebMD.
- ↑ Groundsel
- ↑ 75.0 75.1 75.2 GROUNDSEL, WebMD.
- ↑ Goldenseal, University of Maryland Medical Center.
- ↑ Goldenseal, WebMD.
- ↑ 78.0 78.1 78.2 Goldenseal, American Cancer Society.
- ↑ 79.0 79.1 Henbane, herbs2000.com.
- ↑ HENBANE, WebMD.
- ↑ Dan Rabin, Carl Forget (1998). The Dictionary of Beer and Brewing. Taylor & Francis. xii. ISBN 978-1-57958-078-0. http://books.google.com/?id=XRyxWu8rRnQC&pg=PR12&lpg=PR12&dq=grut+henbane.
- ↑ Horny Goat weed at webMD
- ↑ Epimedium-derived phytoestrogen flavonoids exert beneficial effect on preventing bone loss in late postmenopausal women: a 24-month randomized, double-blind and placebo-controlled trial.
- ↑ Horny Goat Weed (Epimedium)
- ↑ 85.0 85.1 85.2 85.3 HORSE CHESTNUT, WebMD.
- ↑ Horse Chestnut, Drugs.com.
- ↑ 87.0 87.1 HORSETAIL, WebMD.
- ↑ Horsetail, MedlinePlus Supplements.
- ↑ 89.0 89.1 Beriberi, MedlinePlus Medical Encyclopedia.
- ↑ Callilepsis laureola
- ↑ Detection of poisoning by Impila (Callilepis laureola) in a mother and child, Hum Exp Toxicol October 1999 vol. 18 no. 10 594-597.
- ↑ 92.0 92.1 92.2 JIMSON WEED, WebMD.
- ↑ Nightshades, petunias, and lobelia
- ↑ 94.0 94.1 Kava, WebMD.
- ↑ 95.0 95.1 95.2 95.3 Licorice, MedlinePlus Supplements
- ↑ Licorice, Cancer.org.
- ↑ Lily of the valley
- ↑ LILY-OF-THE-VALLEY
- ↑ Lily-of-the-valley, drugs.com.
- ↑ 100.0 100.1 Lobelia, University of Maryland Medical Center.
- ↑ 
- ↑ Manjishta - Uses & Benefits of Manjishta, Rubia Tinctorum, ILoveIndia.com.
- ↑ Madder Root, Powder, W.C. | Herbie's Herbs
- ↑ 104.0 104.1 MADDER ROOT, WebMD.
- ↑ 105.0 105.1 MATE, WebMD.
- ↑ Milk Thistle, WebMD.
- ↑ Mistletoe Herb Medicinal Uses
- ↑ EUROPEAN MISTLETOE, WebMD.
- ↑ 109.0 109.1 Mistletoe, Cancer.org.
- ↑ Manchurian Aristolochia Stem (Mu Tong)
- ↑ Aristolochic Acid – History and use in Chinese Herbal Medicines, Decoded Science, August 28, 2013, Leslie Cohen.
- ↑ 112.0 112.1 112.2 112.3 NEEM, WebMD.
- ↑ from Pubmed
- ↑ Pubmed
- ↑ 115.0 115.1 OLEANDER, WebMD.
- ↑ Tony Isaacs Oleander Protocol For Cancer or AIDS - Cancer Tutor
- ↑ 117.0 117.1 Oleander Leaf, American Cancer Society.
- ↑ Is this even a medical term?
- ↑ Yes, CURE, not just aid or help control.
- ↑ debunked
- ↑ 
- ↑ 122.0 122.1 PARSLEY, WebMD.
- ↑ Pennyroyal, MedlinePlus Supplements.
- ↑ Peppermint oil, MedicineNet.
- ↑ Peppermint oil, WebMD.
- ↑ 126.0 126.1 Roman chamomile, WebMD.
- ↑ Sassafras is a Painkiller
- ↑ 128.0 128.1 SASSAFRAS, WebMD.
- ↑ 129.0 129.1 129.2 SENNA, WebMD.
- ↑ this site will even sell you some
- ↑ "may have clinical relevance" is about the best we've got so far.
- ↑ As shown here
- ↑ Diet for Kidney Stone Prevention, National Kidney and Urologic Diseases Information Clearinghouse.
- ↑ 134.0 134.1 SQUILL, WebMD.
- ↑ STEVIA, WebMD.
- ↑ debunked twice Pubmed
- ↑ Risks associated with St John's Wort.
- ↑ The association between self-reported cataracts and St. John's Wort, Booth JN 3rd, McGwin G, Curr Eye Res. 2009 Oct;34(10):863-6. doi: 10.3109/02713680903144692.
- ↑ 139.0 139.1 139.2 139.3 TEA TREE OIL, WebMD.
- ↑ 140.0 140.1 Valerian, WebMD.
- ↑ Valerian, LiverTox, United States National Library of Medicine.
- ↑ Willow bark, WebMD.
- ↑ 143.0 143.1 143.2 Willow bark, University of Maryland Medical Center.
- ↑ White Willow Bark, About.com, Cathy Wong.
- ↑ 145.0 145.1 145.2 WINTERGREEN, WebMD.
- ↑ Herbalism ***
- ↑ 147.0 147.1 Wintergreen, Drugs.com.
- ↑ "War paint plant 'tackles cancer'". BBC online
- ↑ "Celts' warpaint may be weapon to beat cancer". The Telegraph
- ↑ 150.0 150.1 Wormwood, Cancer.org.
- ↑ 151.0 151.1 He shou wu, NYU Langone Medical Center.
- ↑ 152.0 152.1 152.2 JinBuHuan, LiverTox.
- ↑ Lead poisoning -- Chinese Folk Remedies -- Ji Bu Huan Symptoms
- ↑ Los Angeles County Childhood Lead Poisoning Prevention Program
- ↑ MHRA warns against Traditional Chinese Medicines found to contain Aristolochia