A 35-YEAR-OLD man with end-stage acquired immune deficiency syndrome was admitted to the hospital for severe abdominal pain, abdominal tenderness, and fever. A computed tomographic scan showed colonic distension, thickening of the colonic wall, and a possible rectal mass. Death occurred within 24 hours of admission to the hospital, and permission to perform an autopsy was requested to evaluate the gastrointestinal tract. Recently, he had been given clindamycin for empirically suspected central nervous system toxoplasmosis.