Background: Diarrhea is one of the major health problems in developing countries leading to mortality and morbidity among children under 5 years of age. This study evaluated the antidiarrheal activities of Cucurbita moschata on castor oil-induced diarrheal wistar rats.
 Methods: Thirty (30) wistar rats were divided into six groups of five rats each. All rats except group 1 received 1mL castor oil to induce diarrhea. Groups I and II served as the normal and negative control. Group III received the standard drug (loperamide), groups IV-VI were treated with 100, 200 and 300 mg/kg b.wt of aqueous leaf extract of Cucurbita moschata respectively. Stool inhibition, castor oil-induced enteropooling, and gastrointestinal motility test were determined to evaluate the antidiarrheal effect of the extract.
 Results: Percentage stool inhibition significantly (p < 0.05) increased with increase in the dose of the extract. The percentage distance travelled by the charcoal of the groups treated with the plant extract significantly decreased when compared to the negative control. This decrease was comparable with the group administered loperamide. Administration of aqueous extract of Cucurbita moschata leaf significantly decreased the volume of the intestinal fluid when compared with the volume of intestinal fluid of the negative control and the group administered loperamide. 
 Conclusion: Aqueous leaf extract of Cucurbita moschata possess antidiarrheal activity against castor oil-induced diarrhea.