OBJECTIVE: Ulcerative colitis is a chronically recurrent infl ammatory bowel disease of unknown origin. In the present study, the effect of ginger(rhizome of Zing iber officinale Roscoe) volatile oil on a rat model of colitis was evaluated. METHODS: Volatile oil of ginger with doses of 100, 200, and 400 mg/kg, prednisolone(4 mg/kg), or vehicle were administered orally to groups of male Wistar rats(n = 6) for 5 d. Animals were randomly divided into 6 groups, each group consisting of 6 rats. Colitis was induced by intracolonic instillation of 2 mL of 4%(v/v) acetic acid solution. All rats were sacrificed 24 h later and the tissue injuries were assessed macroscopically and histopathologically. RESULTS: Ginger volatile oil with all doses reduced colon weight/length ratio(P < 0.01) and the effects were similar to the reference drugs. Higher oral doses of volatile oil(200 and 400 mg/kg) reduced ulcer severity(P < 0.05 and P < 0.01), ulcer area(P < 0.01) and ulcer index(P < 0.01). On the other hand, evaluation of microscopic scores showed that the dose of 400 mg/kg of volatile oil was effective to reduce infl ammation severity(P < 0.01) and infl ammation extent(P < 0.05) compared to the control group.CONCLUSION: It is concluded that ginger volatile oil could effectively reduce symptoms of experimental colitis in a dose-dependent manner. OBJECTIVE: Ulcerative colitis is a chronically recurrent infl ammatory bowel disease of unknown origin. In the present study, the effect of ginger (rhizome of Zing iber officinale Roscoe) volatile oil on a rat model of colitis was evaluated. METHODS: Volatile oil of ginger with doses of 100, 200, and 400 mg / kg prednisolone (4 mg / kg), or vehicle were administered orally to groups of male Wistar rats (n = 6) for 5 d. Animals were randomly divided into 6 groups, each Colitis was induced by intracolonic instillation of 2 mL of 4% (v / v) acetic acid solution. All rats were sacrificed 24 h later and the tissue injuries were macroscopically and histopathologically. RESULTS: Ginger volatile oil with (all P <0.01) and the effects were similar to the reference drugs. Higher oral doses of volatile oil (200 and 400 mg / kg) reduced ulcer severity (P <0.05 and P <0.01) ulcer area (P <0.01) and ulcer index (P <0.01). On the othe r hand, evaluation of microscopic scores showed that the dose of 400 mg / kg of volatile oil was effective to reduce infl ammation severity (P <0.01) and infl ammation extent (P <0.05) compared to the control group.CONCLUSION: It is concluded that ginger volatile oil could effectively reduce symptoms of experimental colitis in a dose-dependent manner.