A test meal containing 100 g neutral fat was administered to 10 healthy subjects. Serum concentrations of triglycerides, cholesterol, free fatty acids and gastrin were determined during an infusion of 1000 microng somatostatin/h over 3 hours. In comparison with a control group (infusion of normal saline solution), somatostatin caused almost complete suppression of the triglyceride increase. The free fatty acids showed a slight increase under somatostatin while there was no change in the cholesterol levels. Gastrin release was also completely blocked by somatostatin. The suppression of the serum triglycerides may be explained by the inhibition of digestion and absorption of fat in the small intestine under the influence of somatostatin which suppresses exocrine pancreatic secretion.