Etilefrine, a sympathomimetic drug, was used 11 times in 10 patients with thoracic (n=8) or abdominal (n=2) chyle leak occurring after thoracic surgical procedures. It was given as a 4.2-5 mg/h intravenous infusion. During the 11 etilefrine administrations, three patients had total parenteral nutrition, three had enteral nutrition, three had oral fat-free diet and medium-chain triglyceride supplementation, and two were fed orally without restriction. Daily chyle flow output decreased in all but one patient who was reoperated. Chyle flow output did not decrease relevantly in one patient who was reoperated. Chylothorax recurred after reoperation and etilefrine then induced significant output decrease. In another patient, etilefrine was stopped despite significant output reduction because of interactions with other sympathomimetic drugs used for heart failure. The mean etilefrine treatment duration was 6.4 days (range 4-7). The mean daily output was from 740 ml before etilefrine infusion to 183 ml on the seventh day of etilefrine use. By inducing contraction of the smooth muscle fibres present in the wall of the main thoracic chyle ducts, etilefrine can be considered as a useful adjunct in the management of post-operative chyle leak.