Nine jejunostomy patients were given three low-residue enteral diets in random order through a nasogastric tube. Total bile salt excretion in the jejunostomy contents was 13-17% lower (p less than 0.05) on low-fat diets than on a medium-fat diet. Cholate excretion was 14-20% lower, but chenodeoxycholate excretion showed no difference on the low-fat diets. The study supports the idea of a lower excretion of bile salts to the colon as an explanation of reduced diarrhoea when a low-fat diet is prescribed to patients after ileal resection.