Fifty-three homosexual men with Kaposi's sarcoma (KS) were studied. Twenty-seven had biopsy-proved oral KS, the palate being the most common site. Past or present infections with cytomegalovirus, hepatitis, venereal diseases, and gastrointestinal microorganisms occurred in more than 70%. Oral candidiasis was confirmed in 57%. Heavy marijuana smoking was the most common habit. Transmission of AIDS is thought to be by a viral agent. Precautions involving the use of gloves, eyeglasses, and masks, similar to those recommended for the management of patients with hepatitis B, are urged.