The co-existence of tobacco addiction and alcoholism has been observed in numerous studies. It is estimated that between 71% and 97% of alcoholics also smoke. Several authors have highlighted a positive correlation between alcohol dependency and tobacco addiction. This co-dependency may be problematic during detoxification of alcoholic smokers.

Alcohol can interact with a number of medications, with variable consequences including death. Drug-alcohol interactions are responsible for almost 25% of emergency hospital admissions. Elderly people over 65 years of age, in whom the intake of medications and susceptibility to adverse reactions are greater, are more exposed to the risks of alcohol-medication interactions.

Studies in the 1970s and ?80s, based on representative samples from the general population, suggest that alcohol use during adolescence is a prerequisite to the use and abuse of more dangerous drugs.