In anesthetised animals basal pancreatic blood flow, both in the normal gland and in acute pancreatitis, and basal renal blood flow have been shown to be dependent on prostaglandins (PGs). However, in conscious dogs it has been demonstrated that the reliance of basal renal blood flow on PGs is only apparent, and probably due to the effect of anesthesia and surgery stimulating PG synthesis through enhanced stimulation of the sympathetic nervous system. This study was undertaken to investigate the changes in mean blood pressure, cardiac output, and pancreatic arterial blood flow, relative to the cardiac output, in the normal pancreas, with and without PG synthesis inhibition (indomethacin) in conscious dogs. Blood flows were measured with electromagnetic flow probes. The effects of indomethacin were measured over a 2-hr period and compared to a control group. The results show that the relative pancreatic blood flow is not affected by doses of indomethacin which decrease cardiac output (P less than 0.5). It is suggested that PGs may have no effect on blood flow in the normal pancreas in conscious animals.