Cisplatin-related diarrhea is a relatively common complication in the clinical management of cancer patients and until now no treatment for this condition has been identified. Octreotide has been reported effective in the treatment of 5-fluorouracil-related diarrhea. To assess the safety and efficacy of octreotide in controlling diarrhea caused by cisplatin, 43 patients who had already had diarrhea during the 24-hour period following a previous cisplating administration were randomized to receive either octreotide or placebo during the next cisplatin course. The patients given octreotide experienced less diarrhea (5 vs. 75%, p = 0.01). There were no side effects. We conclude that octreotide is more effective than placebo in controlling diarrhea following cisplatin chemotherapy.