BACKGROUND: We have several times experienced that Crohn's disease has not been diagnosed until several years after the start of oral symptoms. This article presents some patients with oral manifestations of Crohn's disease, as a contribution to more awareness of this possibility. MATERIAL AND METHODS: Clinical and histological data from four patients are presented. RESULTS: All patients had granulomatous inflammation of the oral mucosa. In three patients, the disease started in the mouth. The diagnosis of intestinal Crohn's disease was made from some months up to seven years later. In one patient, no granuloma was found in the intestinal tract, but the patient had intestinal symptoms. Two patients experienced disappointments in their contacts with the local health care system, with considerable delay in diagnosis. INTERPRETATION: We interpret these cases as evidence that a greater awareness of the possibility of Crohn's disease in the oral cavity may lead to a quicker diagnosis, earlier correct treatment, and less patient worry caused by uncertainty.