Output from gastrointestinal fistulae to the skin was measured in five patients during total parenteral nutrition and restricted oral intake. Supplemental infusion of somatostatin during six days caused a significant reduction in discharge in all patients compared to the pretreatment level, but none of the fistulae closed as a result of the treatment. Somatostatin may be considered an adjuvant drug to parenteral nutrition and restricted oral intake in the conservative treatment of external fistulae from the gastrointestinal tract.