The restriction of dietary protein has long been considered a main stay in the therapy of hepatic encephalopathy. More recently it has been recognized that protein energy malnutrition is frequent in advanced liver disease and may adversely affect the patients'outcome. Moreover studies on inter-organ ammonia exchange in liver cirrhosis have shown that the muscle may have a crucial role in ammonia detoxification. In light of these evidences nutritional guidelines have proposed that protein restriction should be avoided in patients with hepatic encephalopathy as protein requirement is even increased in cirrhotic patients. Survey about the current clinical practice show that protein restriction is still considered advisable in patients with hepatic encephalopathy, however a recent trial evidenced that a low protein diet in patients hospitalized for acute hepatic encephalopathy exacerbates protein breakdown without inducing any specific clinical benefit when compared to a normal protein regimen. The relevance of an adequate protein intake and possible strategies to implement protein tolerance are also discussed.