The objective of this study has been to lay the groundwork for a re-evaluation of the place of antibiotics in acute pancreatitis. This section has been devoted to determining if antibiotics excreted by the normal pancreas are excreted similarly in acute pancreatitis. Ten mongrel dogs were studied, each acting as its own control. Day 1: Operation--construction of pancreatic fistula. Day 2: Study of antibiotic excretion. Day 14: Operation--induction of acute focal pancreatitis. Day 15: Study of antibiotic excretion. Antibiotic concentrations in pancreatic fluid were studied by injecting tobramycin intravenously (5 mg/kg). Serum levels and excretion of the drug in the pancreatic secretion were then monitored over the next six hours. Results showed excretion of tobramycin reached bactericidal concentrations in pancreatic fluid from the normal and inflamed pancreas, with no significant differences (p = 0.2) between the excretion rates. The place of antibiotics in acute pancreatitis is discussed. Based on usual pathogens isolated in pancreatic abscesses, and their usual sensitivity patterns, tobramycin with Cephamandole are the antibiotics of choice in acute pancreatitis, and a clinical trial is indicated to evaluate their place in reducing complications and deaths in the disease.