The incidence of antibodies to maize using an immunofluorescent technique has been found to be 14% in controls, 33% in Crohn's disease, 50% in ulcerative colitis and 44% in coeliac disease. This result indicates that humoral immunity to maize is probably unimportant in the pathogenesis of Crohn's disease. The similar incidence of antibodies in the inflammatory bowel disease and coeliac groups suggests absorption of dietary antigen secondary to an increased mucosal permeability.