This paper examines the dynamics of the relationship between drug taking, sexual activity and sexual risk. While epidemiological research has provided essential indicators of levels of drug-taking and sexual risk behaviour, the determinants of the relationship between drug-taking and sexual risk remain unclear. A review of recent epidemiological research indicates two main contentions. First, that the use of certain drugs increases (or decreases) sexual desire and levels of sexual activity. Second, that the use of drugs (licit and illicit) has a disinhibitory effect on safer sex compliance. Critical examination of the literature shows that evidence in support for either of these contentions is both limited and variable. This paper argues that there is little empirical certainty about the causal determinants of the relationship between (a) the reputed pharmacological effects of drug use on sexual activity and (b) the social, situational and cultural factors which may influence sexual activity and safer sex compliance in drug use related encounters. The paper concludes that understandings of the relationship between drug-taking and sexual risk rest as much upon commonsense understanding as on empirical evidence. In response, the paper outlines the needs and parameters of future social research, which as a primary focus aims to examine the social interaction and social relations of drug use and sexual activity.