The goal of the current investigation was to determine antidiarrheal effects of Holarrhena antidysenterica (Family-Apocynaceae) bark ethanolic extract against induced diarrhea in Wistar albino rats. Materials and method: The selected bark part of plant materials were evaluated using pharmacognostic parameters such as ash values, total ash value, soluble extract value etc. Then after standard plant materials was used for extraction process. The developed extract of plant was used for the investigation of diarrheal prevention action. The plant extract was evaluated for castor oil induced diarrhea. The estimation of diarrhea activity assessment was determined using 100, 200mg/kg body wt. orally in albino rat. The inhibition of diarrheal effect of the plant extract on castor oil induced diarrhea was measured by inhibition of dicharge volume of fluid. The diarrhea activity was determined using orally 100, 200mg/kg of plant extract and was noted the percentage inhibition of defecation was calculated for each group, change in fecal consistency, and body weight was recorded for each individual rat for 3 days. The diarrhea activity of plant extract was compare with standard drug Loperamide was given at 5mg/kg body. Results and discussion: Due to castor oil administration there is accumulation of water and electrolytes in the intestinal loop. Loperamide has significantly reduced the mean volume of intestinal fluid in comparison to the control. The plant extract dose of 200mg/kg has significantly reduced the mean volume of intestinal fluid in comparison to control. The plant extract at a dose of 200mg/Kg significantly decreased the propulsion of charcoal meal through the gastrointestinal tract in comparison to the control. Conclusion: Results of evaluation of Holarrhena antidysenterica extract having significant bioactive molecules. This bioactive molecule can be used for the treatment and management of diarrheal diseases.