Antabuse
Antabuse (or disufiram) is a drug that is used to treat alcoholism by producing unpleasant side effects such as vomiting and pain if alcohol is consumed. It works by blocking an enzyme that is responsible for metabolizing alcohol. If a person drinks while on Antabuse they will experience effects such as nausea, vomiting, headache, anxiety, pain, weakness, and blurred vision. Note that this is not a cure for alcoholism, just a type of treatment. Along with therapy and other systems of support it can help a person who has severe issue with alcohol not want to drink anymore. It is essentially a form of the Garcia Effect or conditioned taste aversion which is an aversion to a particular food or smell that was associated with a negative response such as vomiting.