Background: Ulcerative colitis (UC) is a chronic inflammatory tissue disorder (IBD) of autoimmune origin characterized by predominant intestinal symptoms such as abdominal pain, diarrhea, relapses and recurrences of rectal bleeding, which leads to weight loss. Extraintestinal manifestations may also occur, including involvement of the oral cavity. Oral involvement during IBD includes aphthous, plant piostomatitis (PV) and lichen planus (LP). Objectives: the aim of this study was to document oral manifestations in patients with CU and also to assess whether the oral manifestation could predict relapse and remission of CU. Materials and Methods: Fifteen patients (8 men and 7 women) diagnosed with CU were enrolled in gastroenterology clinics (with a disease duration of 5 to 15 years) with healthy controls corresponding to age and sex. All study participants underwent an intraoral examination to evaluate the oral manifestation. The same patients were also asked a series of questions on the questionnaire to evaluate a possible association between the occurrence of oral manifestations and the relapse of a CU episode. Results: PV, mild aphthous ulcer, LP, halitosis, dysgeusia, dry mouth, tongue lining, gingivitis and periodontitis were documented as oral manifestations in UC. PV, mild aphthous ulcer and LP showed recurrence and remission with UC severity. Conclusion: our study revealed numerous and distinct intraoral manifestations in patients with CU. Previous episodes of oral manifestations were also similar and had reported an exacerbation of oral manifestations during relapses. Therefore, oral manifestations can be used as an indicator of relapse in the CU. Keywords: Inflammatory bowel disease, oral manifestations, pyostomatitis vegetans, ulcerative colitis