Vomit therapy

As a dog returneth to his vomit, so a fool returneth to his folly. Vomit therapy was a legitimate treatment for some types of poisoning in Western medicine until recently. Usually (derived from roots of the plant Carapichea ipecacuanha) was advised to induce vomiting. A 2005 analysis concluded that "circumstances in which ipecac-induced emesis is the appropriate or desired method of gastric decontamination are rare." Ipecac is no longer recommended for poison treatment except under rare circumstances under medical treatment.

Ayurveda
In Ayurvedic medicine, vomiting (vamana) is used for prevention or treatment of many disease conditions: acne, anemia, anorexia, asthma, bronchitis (allergic), cold, cough, diabetes, diabetes, dyslipidemia, eczema, edema, epilepsy, fever, hyperacidity, indigestion, loss of appetite, lymphatic obstruction, migraine, nausea, obesity, poisoning, psoriasis, rhinitis, sinus problems, sinusitis, skin diseases, tonsillitis, and urticaria. In Ayurveda, vomiting is usually induced by a drink containing either licorice (Glycyrrhiza glabra) and honey, or calamus root (Acorus calamus). Yes, vomiting has been claimed to prevent anorexia!

While vomiting once in a while is usually not dangerous, excessive vomiting can cause dehydration, esophageal tears, and damage to teeth. Given that vamana has little or no demonstrated efficacy for its many claims, that it can be dangerous, and that there are safe efficacious Western medical treatments for most of the conditions that it is claimed to treat, vamana is not recommended.

Reparative therapy
Vomiting is one of the techniques that has been used in "reparative therapy" of sexual orientation. It is considered ineffective by the American Psychological Association.

Thailand
(วัดถ้ำกระบอก) is a Buddhist temple in Thailand that is known for among other things its opioid drug rehabilitation/detoxification program. The treatment program includes Asian herbal supplements, relaxation and vomiting; supposedly the vomiting part is only 5% of the healing process, though how that's calculated isn't clear. The secret vomiting potion includes 100 or so different herbs. The efficacy of this treatment is unknown, but it has attracted a few Western drug addicts for treatment. In fairness, US treatment of drug and alcohol addiction may not be much better with large amounts devoted to 12-step derived programs, whose efficacy is not very good at all.