The goal of this study was to evaluate the anti-diarrheal properties of the ethanolic extract of stem bark of Oroxylum indicum in castor oil induced rats. Animals were randomly divided into four groups, each group consisting of 6 animals: (Group-1) Normal Control group, (Group-2) Positive control group treated with standard drug (Loperamide, 5 mg/kg, orally), (Group-3) Treatment group (Low dose) treated with Oroxylum indicum stem bark extract (200mg/kg, orally) and (Group-4) Treatment group (High dose) treated with Oroxylum indicum stem bark extract (400mg/kg, orally). The animals of treatment group showed significant deterioration in gastrointestinal floras which cause a significant increase in the movement of the charcoal meal, weight of intestinal content, volume of intestinal content, and percentage inhibition. Treatment with ethanolic extract produced dose dependently significant improvement in gastrointestinal function by preventing the wet sewage production, restricting the passage of enteropooling caused by castor oil, which lowers the weight and volume of intestinal content, decreases mean number of Wet/loose faeces in 5hrs, also significantly increase the movement of the charcoal meal. These findings suggest that the ethanolic extract of the stem bark of Oroxylum indicum possesses anti-diarrheal properties in dose dependent manner. As a result, this plant may have some medicinal potential in humans for the treatment of diarrhea.