Crohn's disease and ulcerative colitis are forms of inflammatory bowel disease. Crohn's disease is present along the entire length of the gastrointestinal tract, and involves the entire thickness of the intestinal wall. Inflammatory changes are discontinuous, with alternating areas of healthy and diseased mucosa. Ulcerative colitis is confined to the mucosa of the colon. Inflammatory changes, as opposed to Crohn's disease, are continuous. Both conditions are characterised by the chronic inflammation of gatrointestinal mucosa, and in some cases extraintestinal manifestations. Oral manifestations of Crohn's disease are: orofacial oedemas, mucosal tags, cobblestoning, hyperplastic gingivitis and aphthous stomatitis. They occur mostly on buccal mucosa, gingiva, lips, vestibule and retromolar area. Orofacial granulomatosis is an uncommon condition amongst patients with oral lesions identical to those of Crohn's disease, yet the intestine is unaffected. Oral manifestations of ulcerative colitis are not as prominent as oral manifestations of Crohn's disease. Most common features are aphthous stomatitis and pyostomatitis vegetans. Treatment of oral lesions focuses on the treatment of the underlying disease. Patients with inflammatory bowel disease are treated with corticosteroids and immune suppressants. Caution is therefore required during dental treatment.