Abstract: OBJECTIVE To investigate the therapeutic effect of Oridonin tablet on acetic acid-induced ulcerative colitis in mice. METHODS Oridonin tablets at different dosages were administered orally to acetic acid-induced colitis mice. After 7 days of treatment, the effects of Oridonin tablet on disease activity (i.e. body weight, stool blood, and stool consistency), colonic macroscopic and histological score, myleoperoxidase activity, and thymic and splenic indexes were evaluated in acetic acid-induced ulcerative colitis in mice. RESULTS Oridonin tablet treatment dose-dependently reduced the disease activity, attenuated colonic inflammation and myleoperoxidase activity, and improved the thymic and splenic indexes in acetic acid-induced ulcerative colitis in mice, especially in high dose of Oridonin tablet treated group. CONCLUSION High dose of Oridonin tablet treatment shows therapeutic effect on acetic acid-induced ulcerative colitis in mice, the underlying mechanism may have close correlation with its anti-inflammatory and immune regulatory effects.