The leaves of Crossepteryx febrifuga (Euphorbiaceae) are commonly used in the Republic of Congo in traditional medicine as a laxative. The present study aims to justify the traditional use of Crossopteryx febrifuga in the treatment of constipation. The acute toxicity of the aqueous extract was evaluated at the doses of 2000 mg/kg and 5000 mg/kg in mice accordance the OECD, (2001) guideline no. 423. The laxative activity of the aqueous extract at doses of 100, 200 and 400mg/kg was evaluated in normal rats, in rats made constipated rats by loperamide hydrochloride as well as on the accumulation of liquid intestinal. The results obtained show that the aqueous extract at a dose of 2000 mg/kg does not modify the general behavior of mice and does not cause mortality. However, sedation and mortality were observed at the dose of 5000 mg/kg of the aqueous extract. Thus, the aqueous extract would be weakly toxic, with an LD50 > 4000 mg/kg. Furthermore, it appears from this study that loperamide caused constipation in all normal rats during the three days of treatment, which resulted in a significant decrease (p ?0.01 and p?0.001) in fecal parameters except the body weight of the animals which increased significantly (p ?0.01) compared to the control group. In addition, Normacol* and aqueous extract (100, 200 and 400 mg/kg) significantly (p?0.001) increase faecal parameters compared to control group. In addition, the aqueous extract significantly increases (p<0.001) the accumulation of intestinal fluid and stimulates the excessive secretion of Na+ ions. These results show that C. febrifuga has laxative properties which could be justified by the presence of anthraquinones, flavonoids, alkaloids and saponosides highlighted in this plant.

Keywords: Crossopteryx febrifuga, aqueous extract, acute toxicity, laxative activity