Acamprosate (calcium acetyl-homotaurine) is a synthetic compound whose chemical structure resembles that of homotaurine, a naturally occurring amino acid. Acamprosate acts centrally and appears to restore the normal activity of glutaminergic neurons, which become hyperexcited as a result of chronic alcohol exposure. Although not yet approved for use in the United States, acamprosate has been available by prescription in France since 1989 and is now available in many other countries throughout the world. This article reviews data from all published double-blind, placebo-controlled clinical trials of acamprosate among alcohol-dependent outpatients. Overall, patients treated with acamprosate exhibited a significantly greater rate of treatment completion, time to first drink, abstinence rate, and/or cumulative abstinence duration than patients treated with placebo. The drug's reliable effect on prolonging abstinence, in conjunction with an excellent safety profile, suggests that acamprosate may be useful for a broad range of patients with alcohol dependence.