Ulcerative Colitis (UC) is a lingering type of Inflammatory Bowel Disease (IBD) which affects the colon mucosa. Ulcerative colitis is majorly associated with oxidative stress and inflammation in colon tissue leading to damage. Averrhoa bilimbi L. fruit is rich in antioxidant phytochemicals including Vitamin C. In the current research, we have evaluated the defence mechanism of Averrhoa bilimbi L. on Ulcerative Colitis (UC). Male wistar rats were treated with Averrhoa bilimbi L. fruit extract (50 mg/kg/bwt and 100 mg/kg/bwt) and a standard drug Sulfasalazine (100 mg/kg/bwt) for 6 consecutive days via intra peritoneally. After one day fasting, rats were given single dose of 3% 2 ml of acetic acid through anal (intra-anal) region to induce Ulcerative Colitis. The protective and therapeutic effect of fruit extract on UC was assessed by comparing the relevant changes observed in the normal and treated group. In treated group the level of mucosal injury was decreased (ulcer score − 2) when compared to the control group (ulcer score − 9). The abnormal increase observed in the inflammation mediator cytokines in control rats, i.e IL-1β, IL-6, TNF-α levels were decreased significantly (**p < 0.01) in the Averrhoa bilimbi L. fruit extract treated groups. The increase in weights of the colon tissue and spleen of the control rats were found to be reduced in treated groups. The levels of inflammatory markers iNOS and COX-2 were also decreased in treated group significantly (**p < 0.01) when compared with the control. Furthermore, the treatment with Averrhoa bilimbi L. fruit extract has shown a significant antioxidant activity in the UC condition by reducing the levels of NO and enhancing the levels of SOD and GSH in the colon tissue. These results demonstrate the effective anti-ulcerative colitis activity of the Averrhoa bilimbi L. fruit extract in experimental wistar rats.