The problem of cocaine dependence remains a major medical, social, and legal concern. Several studies have suggested that disulfiram may be beneficial for the treatment of cocaine dependence. A common assumption has been that disulfiram treatment, by increasing DA availability, enhances the aversive aspects of stimulants. This study aims to measure plasma activity in those with the C/C DBH genotype, which is associated with higher DBH activity subsequently making the disulfiram treatment more effective, as well as determine the effects of treatment with disulfiram on cocaine self-administration using a human laboratory model of cocaine self-administration.