Over the past several decades we have seen an increase in the prevalence of anabolic steroid use by athletes. Because use of anabolic steroids is illicit, much of our knowledge of their side effects is derived from case reports, retrospective studies, or comparisons with studies in other similar patient groups. It has been shown that high-dose anabolic steroids have an effect on lowering high-density lipoprotein, increasing low-density lipoprotein, and increasing the atherogenic-promoting apolipoprotein A. Steroid abuse can also be hepatotoxic, promoting disturbances such as biliary stasis, peliosis hepatis, and even hepatomas, which are all usually reversible upon discontinuation. Suppression of the hypothalamic adrenal axis can also lead to profound adrenal changes that are also reversible with time. Although rare, renal side effects have also been documented, leading to acute renal failure and even Wilms' tumors in isolated cases. Much of our knowledge of these potentially severe but usually limited side effects is confounded by use of combinations of different steroid preparations and by the concomitant use with other substances. Physicians must target their efforts at counseling adolescents and other athletes about the potential harms of androgenic anabolic steroids and the legal options to improve strength and performance.