A hydrogen-gas tissue clearance method measures local blood flow rates in the submucosa of the rat stomach. By using two indicating electrodes, simultaneous measurements of flow rates within the cardiac region and the pyloric section of the stomach were obtained. Valid measurements could be obtained only after the 12th postoperative day and infection was found to cause a statistically significant increase in local gastric blood flow. Recordings made on or after the 14th postoperative day from rats fasted for 12 hours and free from infection are considered to be representative of basal perfusion rates. In such rats the mean blood flow rate in the cardiac section of the stomach was 0.47 ml/gm min and in the pylorus, 0.79 ml/gm min. This difference is significant (P < 0.001). Hypoxia produced significant reductions in local gastric blood flow during the hypoxic period followed by a marked posthypoxia hyperemia.