BACKGROUND : Polyphenolics (flavonoid and phenolic) rich plants are the effective source for the treatment of acute and chronic degenerative diseases including inflammatory bowel disease. OBJECTIVE : This study was aimed to examine the effects of polyphenolics rich leaf acetone extract of P. subpeltata against the indomethacin induced ulcerative colitis in rats. METHODS : Two consecutive days administration of indomethacin produced chronic inflammation in GIT tissues of rats. Further, the plant extract 200 and 400 mg/kg treatment were continued until 11th day. Then hematological, enzymatic antioxidants, MPO and histological evaluations were analyzed. Moreover, the extracts were treated with RAW267.4 cells for the cytotoxicity, NO and TNF-α analysis. RESULTS : The obtained results revealed, that higher dose of the plant extract dropped neutrophil infiltration followed by inhibiting the MPO enzyme levels and controls the enzymatic antioxidants such as SOD, CAT, GSH and LPO. RAW cells study also proved that the plant extract effectively inhibits NO and TNF-α production. CONCLUSIONS : Thus, these results suggest that P. subpeltata extract may have therapeutic potential for the treatment of IBD although further clinical research is still warranted.