Substance misuse by healthcare professionals raises many concerns, including the threat to patient care. This review summarizes the recent literature concerning misuse by doctors (physicians), nurses, dentists, undergraduates and other healthcare workers. Self-medication is common among doctors. Specific specialities are noted to be at higher risk, including emergency medicine, psychiatry, anaesthetics, and nurses in high stress specialities. Most studies are descriptive cross-sectional prevalence studies of self-reported substance use. Dedicated treatment programmes are reviewed, including specific treatment services for addicted professionals created at national, regional and local levels. A recognition of the risk of substance misuse should be explicitly included early in the training of healthcare workers. Specialist treatment programmes should be holistic in approach, and should not concentrate solely on substance misuse issues but include the treatment of depression, anxiety, sexual disorders and adjustment disorders.