A prospective study of coagulation disturbances and endotoxemia in 42 patients having major pancreatic or biliary surgery was performed. Endotoxin, soluble fibrin, and fibrin degradation products were measured before and after operation in 28 patients with obstructive jaundice and in 14 nonjaundiced controls. In the control group there was one death and no unexplained fever or postoperative hemorrhage. The jaundiced group had more complications: seven deaths, nine episodes of fever, and six episodes of hemorrhage. Soluble fibrin was detected only in patients with obstructive jaundice, in whom it occurred in 38 percent before operation. Positive endotoxin assay was as common in control patients as in the jaundiced group, but in the latter endotoxin was associated (p less than 0.05) with increased FDP and soluble fibrin. Patients with endotoxin or increased FDP levels before operation for jaundice carry a poor prognosis (7 of 11 died). Preoperative bowel preparation in 16 of the jaundiced patients did not affect the outcome.