['In this study, mucosal antioxidant defense was investigated in the biopsy samples from 12 patients with active ulcerative colitis and from 13 patients under remission.', 'Biopsy samples obtained from healthy colon parts of the same subjects were used as control.', 'No changes were observed between superoxide dismutase, glutathione peroxidase and catalase enzyme activities of control or inflamed biopsy samples. However, antioxidant potential values were found to be higher and malondialdehyde levels lower in inflamed samples compared with controls.'] Is mucosal antioxidant defense impaired in ulcerative colitis?