Postprandial plasma secretin and CCK release were investigated in patients with gastrectomy and pancreatoduodenectomy reconstructed by Billroth-I, Billroth-II, Roux-en-Y and Child's methods. Plasma secretin response were significantly decreased in patients with B-I and B-II reconstruction after gastrectomy, especially in total gastrectomized patients with Roux-en-Y reconstruction, which might be resulted from the reduced gastric acid secretion following gastrectomy. CCK release was not significantly changed in patients with various reconstructions after gastrectomy compared with control group. In patients with pancreatoduodenectomy reconstructed by Child's method plasma secretin and CCK release were significantly decreased as compared with normal controls.