Diarrhea is a common cause of death in developing countries. It is also one of thernprimary causes of morbidity and mortality on a global scale, leading to 1 billionrndisease episodes and 1.8 million deaths each year, among children under five years ofrnage. Due to limitations associated with various treatments available, the need forrndeveloping newer drugs is imperative. This study aimed at investigating the in vivornanti-diarrheal activity of 80% methanolic extract of leaves from the traditionally usedrnmedicinal plant, named Croton macrostachys. The effect of the 80% methanolicrnextract in rodents on castor oil-induced diarrhea, intestinal transit, and enteropoolingrnwas evaluated at doses of 200, 400, and 600 mg/kg body weight. The anti-diarrhealrnindex (ADI) was calculated combining all diarrhea indicators to see the relative effectrnof the extract. In castor oil induced diarrhea, the extract produced a significant (p