Since oral lesions appear to occur more commonly in patients with Crohn's disease (CD) than in normal controls or patients with ulcerative colitis, it has been suggested that a deficit of locally produced IgA allows the invasion of the oral mucous membrane by antigens and contributes to the production of oral lesions. In connection with this hypothesis, the concentrations of IgA, IgM, and IgG in whole and parotid saliva were investigated by the ELISA technique in 20 patients with CD and 20 healthy subjects matched for dental status. IgA predominated in whole and parotid saliva in both patients and controls, and in both groups whole saliva had higher levels of IgA, IgM, and IgG than parotid saliva did. Compared with the controls, IgA, IgM, and IgG levels were significantly elevated in the whole saliva of CD patients. However, no correlation was found between immunoglobulin levels and age, sex, therapy, duration, localization, or activity of the disease.