The treatment of common diseases remains a problem for African populations, despite the fact that African pharmacopoeia abounds with numerous medicinal plants, like Alchornea cordifolia, a plant used by many traditional healers as an antidiarrhoeal. The aim of this study was to evaluate the in vivo anti-diarrhoeal potential of a decoction of Alchornea cordifolia leaves in experimental rats. Antidiarrhoeal activity was assessed in an experimental castor oil-induced diarrhoea model. It was evaluated in preventive and then curative model. Percentages of diarrhoeal stool inhibition were calculated in each case. Phytochemical screening was carried out in search for major phytochemical groups that could provide anti-diarrhoeal activity. In rats pre-treated with A. cordifolia leaf decoction, there was a reduction in the number of diarrhoeal episodes at doses of 100 mg/kg, 200 mg/kg and 400 mg/kg bw. The percentages of inhibition were 34.21%, 76.80% and 52.83% respectively, compared to 54.10% for loperamide. A. cordifolia at doses of 200mg/kg to 400mg/kg also delayed the onset of diarrhoea. For the evaluation of curative antidiarrhoeal activity, administration of A. cordifolia decoctate led to a reduction in diarrhoeal episodes at doses of 100mg/kg, 200mg/kg and 400mg/kg bw. The percentages of inhibition were 39.35%, 63.59% and 50.16%. Loperamide inhibition was at a rate of 57.27%. Phytochemical screening revealed the presence of tannins known to be responsible for this anti-diarrhoeal activity. Alchornea cordifolia therefore has anti-diarrhoeal properties that could be used in phytomedicines.