Since the late nineteenth century, protein restriction has been shown to improve hepatic encephalopathy. However, malnutrition has been described in up to 60 % of cirrhotic patients and is associated with increased mortality. Furthermore, emerging clinical evidence has revealed that a large proportion of cirrhotic patients may tolerate normal protein intake. However, approximately one third of cirrhotic patients with hepatic encephalopathy may need a short course of protein restriction, in addition to maximum medical therapy, to ameliorate the clinical course of their hepatic encephalopathy. For patients with chronic hepatic encephalopathy who are protein-sensitive, modifying their sources of nitrogen by using more vegetable protein, less animal protein, and branched-chain amino acids may improve their encephalopathy without further loss of lean body mass. In conclusion, among cirrhotics with hepatic encephalopathy, modulation of normal protein intake must take into account the patient's hepatic reserve, severity of hepatic encephalopathy, and current nutritional status.