Twenty six infant boys, aged 4 to 18 months, suffering from persistent diarrhoea and 25 age matched healthy controls without diarrhoea were given a diet based on rice powder, egg white, glucose, and soya oil. The clinical efficacy of the diet was studied and a 72 hour metabolic balance study was done. Twenty one patients recovered from diarrhoea within seven days. Median coefficients of absorption of nutrients in persistent diarrhoea patients were 68.0% (range 28.0 to 92.0) for total energy, 60.0% (range 21.0 to 97.0) for fat, 53.0% (range -122.0 to 82.0) for nitrogen, and 81.0% (range 23.0 to 97.0) for carbohydrates. The corresponding values among the control subjects were 90.0% (range 76.0 to 99.0), 95.0% (range 71.0 to 99.0), 70.0% (range 10.0 to 95.0), and 93.0% (range 85.0 to 98.0) respectively. Absorption of all macronutrients in the control subjects was on average significantly higher than in the patients. Nutrient absorption is substantially reduced in persistent diarrhoea and a rice based diet is clinically effective in most patients.