Diarrhoea is one of the leading causes of death in children worldwide, accounting for 1 out of every 9 deaths in children. Therefore, in an attempt to tackle this disease, we investigated the effects of selenium on experimentally induced diarrhoea in animals. Female albino rats weighing 100-150 g were used and diarrhoea was induced by oral administration of castor oil, after which the animals were treated with 100 or 200 µg/kg selenium orally to investigate its effect on the number of wet feaces output. Experiments on intestinal enteropooling and intestinal motility of activated charcoal meal were also carried out. The two doses of selenium (100 and 200 µg/kg) significantly (P < 0.01) reduced the number of wet feaces and also significantly (P < 0.001) reduced the volume of intestinal fluid content, with 200 µg/kg producing 43.81% inhibition of fluid content, while the standard drug loperamide caused 54.30% inhibition. Furthermore, 100 µg/kg and 200 µg/kg selenium significantly (P < 0.001) reduced intestinal motility; producing 28.49% and 29.91% motility inhibition respectively with respect to control, while atropine inhibited intestinal movement by 49.2% with reference to control. In conclusion, selenium possesses anti-diarrhoeal effects through anti-secretory and anti-motility mechanisms.