During the past year, there have been important advances in the field of parasitic diseases of the gut. An immunodiagnostic test that allows the rapid identification of pathogenic Entamoeba histolytica has been developed. Two new parasites that produce diarrhea have been characterized. Cyclospora, a cyanobacterium-like organism, is prevalent worldwide, affects immunocompetent individuals, and has been described as a cause of traveler's diarrhea. Encephalitozoon sp has been reported in patients with AIDS; however, unlike Enterocytozoon bieneusi, it has the potential for systemic dissemination. Treatment of Trichuris trichiura has been demonstrated to rapidly correct the cognitive deficit present in children with trichuriasis. Lastly, combined treatment of hydatid disease by percutaneous drainage plus albendazole has been shown to be an effective form of management.