Gastric blood flow in man can be measured with an isotope washout technique, utilizing 85Krypton . Measurements are performed intraoperatively, during general anesthesia, after intraarterial injections of the tracer into the stomach wall. Both total blood flow to the stomach and the flow distribution to the separate wall layers can be estimated. The antrum and the body of the stomach can be studied separately. Repeat measurements are possible, enabling the blood flow to be studied both at rest and/or after induction or inhibition of acid secretion.