Purpose: To investigate the antidiarrheal activity of the aqueous extract of the stem bark of S. ellipticum (Euphorbiaceae) (AESE).

Methods: AESE was prepared by decoction of the powder from the dry stem bark of S. ellipticum. Its oral antidiarrheal effect was evaluated in vivo at the doses of 5.2, 10.4 and 20.8 mg/kg on castor oil induced diarrhea and on gastro-intestinal transit. AESE was also evaluated in vitro (0.125 – 4 mg/ml) on ileal smooth muscle motility. The acute oral toxicity of AESE (5, 10, 15, 20 and 25 mg/kg) was also assessed in mice.

Results: AESE significantly and dose dependently delayed  the time of appearance of the first stools, decreased the frequency of defecation and the intestinal transit with respective percentage of 319.14, 62.50 and 36.51 % at the dose of 20.8 mg/kg in comparison with negative control (distilled water). AESE, in a concentration-dependent manner, reduced the tone and amplitude of spontaneous contractions of the ileal smooth muscle with EC50 of 33.29 and 45.43 µg/ml, respectively. None of the doses used in acute toxicity test induced any significant behavioral changes or mortality.

Conclusion: These results suggest that AESE possesses antidiarrheal properties mediated at least partially by the inhibition of intestinal motility and may be devoid of acute toxicity.