The morphologic features of the gastric mucosa in patients with cirrhosis have been well investigated. The aim of this study was to evaluate its functional disruption by measuring the gastric potential difference. Forty patients were investigated, 12 control subjects and 28 consecutive cirrhotic patients with endoscopically proved congestive gastropathy. Potential difference was measured the morning, on an empty stomach, at least 3 days after endoscopy; the method used a double channel gastric perfused probe placed under fluoroscopy 10 cm above the cardia, and a subcutaneous reference, both connected to a millivoltimeter via gelose agar-KCl bridges. Potential difference was recorded in each case 20 min before (baseline) and after local instillation of lysine acetylsalicylate (500 mg) as a provocative test. Cirrhotic patients had significantly lower basal potential difference than controls (-28.3 +/- 1.5 mV vs -33.8 +/- 1.3mV, p = 0.007). Potential difference was significantly lower in patients with severe gastropathy than in patients with mild gastropathy (-20.5 +/- 2.1 and -28.9 +/- 1.6 mV, respectively, p less than 0.01). After stimulation with acetylsalicylate, the area under curve and the irritability index were greater in patients with gastropathy (81.4 +/- 12.8 vs 41.2 +/- 8.6 mV.min, p = 0.032 and 0.935 +/- 0.19 vs 0.290 +/- 0.07 mV.mV.min, p = 0.022, respectively). These differences were explained by a higher drop in potential difference (delta DPmax/baseline; 28.1 +/- 3 vs 16.1 +/- 3 p. 100, p = 0.006) whereas basal return time remained unchanged (16.2 +/- 2.1 vs 13.7 +/- 2.2 min).(ABSTRACT TRUNCATED AT 250 WORDS)