Aim: Aim: Euphorbia prostrata (Euphorbiaceae) is traditionally used in Cameroon for the treatment of many diseases, including diarrhea. We investigated the acute toxicity and effect of the aqueous ethanol extract of the plant on gastrointestinal propulsion, in vitro bacterial growth and in vivo bacillary dysentery. Materials and Methods: Materials and Methods: Diarrhea was induced by oral administration of 12 × 10 8 Shigella dysenteriae type 1 (Sd1) cells. Diarrheic rats were treated for 5 days with 10, 20 or 40 mg/kg extract or 20 mg/kg norfloxacin. The faeces frequencies and the number of Sd1 were assessed and the death rate recorded. Results: Results: The aqueous ethanol extract of E. prostrata was not toxic. In vitro, the minimal inhibitory and minimal bactericidal concentrations of the extract were 3,500 and 12,000 µg/ml, respectively. In vivo, diarrhea went along with increase in faeces frequency (P < 0.01 by the 3 rd day), increase in the bacterial population to a maximum on the 2 nd day after infection (P < 0.01). The death rate in diarrheic control group was 100% by day 6. E. prostrata extracts (20 and 40 mg/kg), like norfloxacin, reduced the bacterial growth (P < 0.01), so that by the 6 th day Sd1 density was <100 and no death was recorded. There was a significant (P < 0.01) reduction in faeces frequencies. The extract exhibited notable (P < 0.01) inhibition of intestinal propulsion. Conclusion: Conclusion: The results suggest that E. prostrata possesses bactericidal and antidiarrheic properties and could be a therapeutic alternative for diarrheas of bacterial etiology.