Ten unselected African patients infected with human immunodeficiency virus (HIV) and with slim disease were evaluated using physical examination, anthropometric measurements, Karnovsky performance score, and muscle biopsy. All had marked weight loss (36.8 +/- 10.8%) with extreme fatigue, marked diffuse wasting with significantly decreased circumferences of arms, thighs and calves (P < or = 0.002), and a low Karnovsky performance score (range 30-70). Mild to moderate motor deficit (in 9/10 patients) contrasted with the major amyotrophy. Chronic diarrhoea (in 7/10) and/or prolonged fever (in 7/10) were always associated with the amyotrophy. Atrophy of muscle fibers was the main finding of muscle biopsy. Only 5 patients met the CDC criteria for the 'HIV wasting syndrome'. We conclude that slim disease, which is highly suggestive of the acquired immune deficiency syndrome (AIDS) in Africa, is a condition associated with chronic diarrhoea and/or prolonged fever, that encompasses the 'HIV wasting syndrome' sensu stricto and probably other debilitating diseases associated with AIDS, such as tuberculosis.