Just as drugs that enhance exercise capacity and/or athletic performance are often called "ergogenic," drugs that impair these functions can be termed "ergolytic." Today's athletes hear too much about the former and too little about the latter. Ergolytic drugs used today by certain athletes include alcohol, marijuana, smokeless tobacco, cocaine, antihypertensives, eye drops, and diuretics. Some antidepressants, too, can be ergolytic, as well as some antihistamines and other common drugs--even caffeine--in some settings, for some people. Internists can help their fitness-minded patients by educating them about ergolytic drugs and by tailoring their management to foster peak performance at work and play.