Based on the notion that reductions in pancreatic blood flow may play a role in the pathophysiology of chronic pancreatitis, a method for measuring pancreatic blood flow, using H2 gas clearance with a ductal electrode, was developed. Preliminary animal experiments using this methodology suggest that the fibrotic pancreas behaves like a closed compartment. The scarring results in ductal and interstitial hypertension, which decreases pancreatic blood flow. This reduction in blood flow may be important in both the pathogenesis of the disease as well as the etiology of the pain. Preliminary human studies, measuring pancreatic blood flow with an H2 electrode placed endoscopically, support these findings. Further studies will be necessary to confirm this novel hypothesis.