Teetotalism is complete abstinence from the consumption of alcoholic beverages. It is often used synonymously with temperance, but that is a change from the original meaning of temperance which is to temper (control or limit) one's use of alcohol. Eventually temperance came to mean the same thing as teetotalism, which means to never touch even a drop of alcohol.
 The name
The name "teetotalism" has nothing to do with drinking tea instead of alcohol, or with playing golf. It stems from the notion of "Total abstinence, with a capital T".
Teetotalism is the official dogma of many religions, mostly fundamentalist ones, including the Mormonism, Islam, and many Baptist and Pentecostal Christians. It is also the doctrine of many approaches to recovery from alcoholism such as that of Alcoholics Anonymous who teach that once a person is an alcoholic they are an alcoholic for life, and drinking even a drop will cause them to relapse.
Some studies have shown that alcohol is actually good for your health, and therefore being teetotal must, by extension, be bad for you. It has been shown with general health and obesity and has been attributed to social factors and antioxidants. Of course, it's only good for you in moderation, but is this really the case?
It has been postulated that these studies may show alcohol is "good" for you because the experiments are not properly controlled, that is, the two groups are not fully like-for-like. Teetotallers are wide variety of individuals (not just those abstaining for religious reasons) and include recovering alcoholics and those that can't drink for health reasons (this is particularly true of those who are absolute in their avoidance of drink, rather than just not being big drinkers). This effect would skew the health of the teetotal "control" groups and give a false impression that drinking in moderation may be good for you.
 See also
- Alcoholics Anonymous
- Mothers Against Drunk Driving
- Prohibition Party
- Word of Wisdom