There is conflicting evidence concerning the effects of portal hypertension on the gastric mucosa. This paper summarises the histological and haemodynamic alterations which are present in both human and experimental portal hypertension. Despite the fact that histological studies suggests that the gastric mucosa is an oedematous plethoric structure in portal hypertension, haemodynamic studies show that gastric mucosal blood glow is at least maintained if not increased in portal hypertension. The term "active" rather than "passive" congestion is a more appropriate description of the basic change present in the gastric mucosa in portal hypertension.