Acquired immunodeficiency syndrome (AIDS), with its attendant sequelae of opportunistic infections and aggressive lymphatic malignancies, continues to dominate the world's medical literature. Pneumocystis carinii pneumonia (PCP) remains as the most commonly encountered infection in AIDS and an early cause of morbidity and mortality. Current therapy for PCP revolves around the administration of either pentamidine isoethionate or trimethoprim-sulfamethoxazole; however, the major AIDS centers report a high incidence of adverse drug reactions to these drugs. We describe an association with human immunodeficiency virus (HIV) infection in a hemophiliac with multiple drug-related hypersensitivity reactions, which include constitutional, dermatologic, and pulmonary manifestations. This observance is intriguing and suggests that the presence of HIV infection may predispose a patient treated with a multitude of drugs and medications to a higher incidence of adverse reactions.