Abstract
Two homosexual Danish men with the acquired immunodeficiency syndrome (AIDS) contracted cryptosporidium enterocolitis. One patient died in another opportunistic infection, the other developed severe chronic enterocolitis with malabsorption. The cryptosporidia escape detection on routine stool examination, but are easily demonstrated by a modified Ziehl-Neelsen stain. It is suggested that this procedure should be applied when persons from AIDS high risk groups or patients with other forms of immunological incompetence develop prolonged diarrhoea.