A large body of data, as well as clinical experience, link prescribed medications and substances of abuse with sexual dysfunction. This review surveys the relevant literature and summarises key points relating various classes of medications and their possible sexual side effects. Surprisingly, there were very few carefully designed, well organised, systematic studies of the effects of medication upon sexual performance. The preponderance of data is in the form of either case studies or collections of patient reports of side effects. As a result, there are great variations in the reported rates of sexual disturbances associated with the administration of a given medication. A further difficulty is the lack of precision in the use of terms which describe the various sexual disorders. A final problem is the almost total lack of data concerning both disordered and normal sexual functioning in females.