Malaria causes a number of clinical complications, including diarrhoea. There are relatively few reports on the frequency of diarrhoea in malaria, but diarrhoea attributable to malaria is thought to be more common among children and nonimmune adults with hyperparasitaemia. The reported incidence of diarrhoea during malaria varies from 5 to 38%. The pathological changes in patients infected with malaria are very complex and involve many organs, including the small bowel. However, the causes of gastrointestinal manifestations during malaria are still not clear, and the mechanism of diarrhoea during malaria is likely to be multifactorial. Massive gastrointestinal bleedings with multiple foci of mucosal haemorrhage have also been observed. Tumor necrosis factor has been implicated in malaria and free oxygen radicals which can cause tissue injury in the liver, pancreas and intestine are enhanced during malaria infection; this can result in various disorders of the digestive system including diarrhoea and intestinal bleeding. Prostaglandins and cyclic AMP may also be involved in the development of diarrhoea in malaria.