Elimination rate (K) of intravenously given triglyceride was studied in seventeen patients who underwent elective abdominal operations, and levels of adrenaline, noradrenaline, insulin and blood sugar were simultaneously measured, as stress-indices. All these indices, except for the insulin/blood sugar ratio, increased post-operatively. The postoperative K value increased significantly in comparison with the preoperative value. There was no significant correlation between K value and any of the stress-indices. These results suggest that the initial catabolism of the lipid emulsion triglyceride is enhanced by surgical stress.