Ulcerative colitis is one of the inflammatory bowel diseases that manifest itself by uncontrolled inflammation of colon. The objective of this work was to evaluate the effects of aqueous extract of Waltheria indica on acetic acid-induced ulcerative colitis in rats. Six (6) groups of five (5) rats each, were anesthetized with a ketamine (50 mg/kg)/valium (10 mg/kg) mixture after eighteen (18) fasting hours. Colitis was induced by intrarectal administration of 1 mL of acetic acid (5%) in animals. Five (5) hours later, the normal control (NC) and the colitis control (CC) received distilled water (10 mL/kg bw), the positive control (Pre5) received prednisolone (5 mg/kg) and the other three test groups received the W. indica extract at 50 (Wi50), 100 (Wi100) and 200 (Wi200) mg/kg bw, orally for 7 days. At the end of the treatment, the animals were sacrificed and the blood was collected from the carotid artery, part in the ethylenediaminetetraacetate (EDTA) tube for hematological analyzes and part in dry tubes for biochemical assays. The abdomen was then opened, the colon, liver, spleen, lungs and heart were removed, drained, weighed and the indexes of each organ were determined. The extract at 200 mg/kg reduced myeloperoxidase (MPO) and inhibited the production of interleukin-1 beta (IL-1beta) and interleukin-6(IL-6) in the colon and serum. The extract significantly increased the blood platelet level of the colitis rats. Thus, these results suggest that Walthera indica extract may have therapeutic potential for the treatment of inflammatory bowel diseases.