Inflammatory bowel disease (IBD) comprises two chronic, tissue-destructive, 
clinical entities: Crohn's disease (CD) and ulcerative colitis (UC), both 
immunologically based. Bowel symptoms are predominant, but extra-intestinal 
complications may occur, including involvement of the oral cavity. Oral 
involvement during IBD includes several types of lesions: the most common are 
aphthae; uncommon lesions include, among others, pyostomatitis vegetans and 
granulomatous lesions of CD. Starting with a presentation of six patients with 
oral manifestations, which were crucial for the final diagnosis of IBD, a review 
on the subject is presented. Oral involvement in IBD may be previous or 
simultaneous to the gastrointestinal symptoms. However, in the majority of 
cases, bowel disease precedes the onset of oral lesions by months or years. In 
many patients, the intestinal symptoms may be minimal and can go undetected; 
thus, most authors believe that the bowel must be thoroughly examined in all 
patients with suspected IBD even in the absence of specific symptoms. Usually, 
the clinical course of oral lesions is parallel to the activity of IBD; 
therefore, oral manifestations are a good cutaneous marker of IBD.