The frequency of gastroduodenal lesions has been investigated in 142 patients with liver cirrhosis of various degrees of severity and in 63 patients with mild liver disease (controls) in whom liver biopsy excluded nodular regeneration. Cirrhotic patients were subdivided in three groups according to the Pugh modification of the Child-Turcotte criteria. Although the frequency of peptic ulcer was not different, gastroduodenal erosions were observed more frequently in cirrhotics than in controls (29.6% vs 11.1%, P less than 0.01). The occurrence of erosions was related to the severity of the disease: in Child A and B patients their frequency was 21 and 26% respectively, but rose to 48.4 (15 of 31 vs 7 of 63 in controls, P less than 0.001) in the Child C group. Both mild and severe gastroduodenitis occurred more frequently, although not significantly, in patients with liver cirrhosis. All together one or more endoscopic lesions were observed in almost 60% of cirrhotics but only in 25.4% of controls (P less than 0.001). In conclusion, our data do not show an increased prevalence of peptic ulcer in cirrhotic patients; in contrast, liver cirrhosis is significantly associated with the endoscopic finding of gastroduodenal erosions, especially in the more advanced stages of the disease. These findings would suggest a cautious use, in cirrhotic patients, of drugs which may damage the gastroduodenal mucosa; moreover, long-term administration of antacids or of other drugs with a protective effect on gastroduodenal mucosa might be taken into consideration for Child C patients.