Disulfiram (AntabuseTM) is principally used in the treatment of alcohol use disorders for its aversive properties. The cocaine-specific action of disulfiram is thought to be based on the suppression of alcohol-related cues for cocaine use or through inhibition of a dopamine metabolising enzyme that leads to excessive dopamine levels associated with aversive effects including heightened anxiety and paranoia. Cocaine administration in subjects pre-treated with disulfiram has been associated with dysphoria and anxiety that was initially attributed to elevated plasma cocaine concentration (McCance-Katz, Kosten & Jatlow, 1998). A study of 122 people dependent on both cocaine and alcohol randomised into five groups (12-step n=25; CBT n=19; clinical management + disulfiram n=27; 12-step + disulfiram n=25; CBT + disulfiram n=26) found disulfiram was significantly associated with better retention and abstinence from alcohol and cocaine use compared to no pharmacotherapy (Carroll, Nich, Ball, McCance & Rounsaville, 1998). Encouragingly, the main effects of disulfiram on cocaine and alcohol use were sustained at one-year follow-up (Carroll et al., 2000). While the role of alcohol as a potent conditioned cue for cocaine craving may have been explanatory, cocainespecific effects were also possible.Two placebo controlled studies have reported positively on the effect of disulfiram in promoting cocaine abstinence in 20 buprenorphine maintained patients (George, Chawarski, Pakes, Carroll et al., 2000) and 67 methadone patients (Petrakis, Carroll, Nich, Gordon et al., 2000). Alcohol use was minimal in both studies. Another potential mechanism for disulfiram is the inhibition of dopamine -hydroxylase, an enzyme that metabolises dopamine. When combined with cocaine-boosted neural dopamine, excessive dopamine levels may cause unpleasant effects, including anxiety and paranoia, (Petrakis et al., 2000) and consequently may increase cocaine toxicity (McCance-Katz et al., 1998).