&NA;Parasitic infections of the gastrointestinal tract constitute a major cause of morbidity and mortality around the world. The study of the immunologic and molecular biologic aspects of parasitic infections has become the leading edge of research in this area. In the past year, DNA probes have been developed that can identify pathogenic and nonpathogenic strains ofEntamoeba histolytica.New immunoassays for the diagnosis of amebiasis and cryptosporidiosis have been reported. Using animal models, the severity of intestinal cryptosporidial infection was significantly reduced by oral administration of anti‐Cryptosporidiummonoclonal antibodies. Evidence was found to suggest that production of IgE is required for the development of protective immunity against schistosomiasis; an IgG response was associated with an increased risk of reinfection. Two interesting review articles on the management of hydatid disease and portal hypertension secondary to schistosomiasis were published.Current Opinion in Gastroenterology 1992,8:101‐109