To characterize bleeding from gastric red spots in patients with cirrhosis, three groups of patients were studied: (a) 11 cirrhotic patients bleeding from gastric red spots, (b) 18 nonbleeding cirrhotic patients without gastric red spots, and (c) 13 noncirrhotic patients with endoscopic normal mucosa (controls). Histologic examination of antral biopsy specimens revealed a diffuse capillary ectasia without inflammation in 8 of the 11 cirrhotic patients with gastric lesions. Morphometric analysis disclosed a significantly greater mean mucosal capillary cross-sectional area in cirrhotic patients with gastric lesions (mean +/- SE, 1371 +/- 320 microns2) than in those without gastric lesions (541 +/- 61 microns2) (p less than 0.005) or controls (353 +/- 20 microns2) (p less than 0.001). Hypergastrinemia was detected in 8 of the 11 cirrhotic patients with lesions, in 2 of the 18 cirrhotic patients without gastric lesions, and in none of the controls (p less than 0.001). Gastrin serum levels correlated significantly (r = 0.80) with mean mucosal capillary cross-sectional area in patients with cirrhosis. Pepsinogen I serum levels below 20 ng/ml were observed in 7 of the 11 cirrhotic patients with lesions, in 1 of the 18 cirrhotic patients without lesions, and in none of the controls. These data indicate that bleeding from gastric red spots in patients with cirrhosis is a distinct entity characterized by vascular ectasia of the gastric mucosa. This condition seems to be associated with hypergastrinemia and low serum levels of pepsinogen I.