Drainage of pancreatic juice uncontaminated by bile or intestinal contents is observed infrequently in clinical practice. Two such patients seen recently gave us the opportunity of determining the excretion of antibiotics by the pancreas. The excretion of erythromycin, streptomycin, and chloramphenicol in fluid collected by means of a T-tube in the main pancreatic duct was measured in a patient with chronic relapsing pancreatitis and the results reported.2 Subsequently, tetracycline was found not to be excreted in pancreatic fluid of this patient after intravenous administration. This report concerns assays made in the second patient, to whom, in addition to the four antibiotics mentioned above, oleandomycin and Sigmamycin (a combination of tetracycline and oleandomycin buffered with ascorbic acid) were given. Report of a Case A 45-year-old white man was admitted to the Veterans Administration Research Hospital on July 22, 1957, with an eight-day history of pain in the epigastrium, nausea, and