In young adult female rats with a cecal stoma, administration of hexadecane into the stomach (750 or 500 mg) and into the ligated colon (250 mg) enhanced 2- to 3-fold the intestinal excretion of [14C]hexachlorobenzene. Apparent sites of increased transferral from the blood into luminal contents were (caudal) ileum, cecum and colon. Presence of nonabsorbed hexadecane in luminal contents seems to be a prerequisite for the effects. Results support previous reports that enhancement of intestinal excretion of lipophilic chemicals by liquid paraffins takes place in the large intestine.