GSH and its related enzymes are one of the protective mechanisms vs. the oxidative damage, both in the circulation and in various tissues, including gastric mucosa. Patients with liver cirrhosis frequently suffer from a gastropathy caused by portal hypertension and they present low circulating levels of GSH. Aging processes cause an increase of gastric damage, of lipoperoxidative phenomenons, and a decrease of GSH in animals. The aim of this study was the evaluation, in humans, of the effect of both these factors, age and liver cirrhosis, on the global pool of GSH and on the antioxidant capability of the cells of gastric mucosa. Therefore, we evaluated the effect of liver cirrhosis and age on the circulating levels of GSH, both in the plasma and in the erythrocytes, and the GSH concentration and the activity of the total GSH-transferase (GSH-T) in gastric mucosa of healthy subjects and in patients affected by liver cirrhosis. Age, but not liver cirrhosis, induced a significant decrease of GSH and GSH-T activity in gastric mucosa; on the contrary, the plasma levels of GSH decreased in cirrhotics but not in elderly healthy subjects. In the erythrocytes, GSH was affected by both these factors (age and liver cirrhosis). These findings indicate that both in patients with liver disease and in elderly healthy subjects the GSH-related cellular defensive mechanisms are depressed and therefore susceptibility to oxidative damage may increase.