Bile salt malabsorption in the radiation syndrome.

The fraction of faecal activity (FBS) excreted after intravenous administration of 14C-labelled cholic acid was measured in 20 patients with gastrointestinal symptoms (diarrhoea, abdominal pains, malabsorption and rectal haemorrhage) after pelvic irradiation. An FBS excretion of 52 +/- 16 per cent (mean +/- SD) was found in 13 patients with diarrhoea and 18 +/- 12 per cent in 7 patients without diarrhoea. In normals the excretion is not above 18 per cent. Bile salt malabsorption appears to be an important factor in the pathogenesis of diarrhoea in these patients.