Safety and Efficacy of AST-120 Compared to Lactulose in Patients With Hepatic Encephalopathy

This is a multi-center, open-label, four week trial comparing AST-120 to lactulose in patients with mild (Stage 1-2) hepatic encephalopathy. Patients will be randomized into two groups: * Lactulose * AST-120 Patients meeting the inclusion criteria will take either AST-120 or lactulose for 4 weeks (28 days). AST-120 will be distributed in 2 gram sachets to be taken four times daily. Lactulose will be taken in the same formulation, at the same dose and frequency as previously prescribed for the individual patient. Lactulose naïve patients who are randomized to lactulose will receive an initial dose of 30cc twice a day. The dose should be titrated at the discretion of the investigator until the patient is experiencing 2-3 soft stools per day. Patients randomized to AST-120 will receive 2 grams four times a day for the duration of the study. Titration of AST-120 will NOT be allowed. Patients will be evaluated throughout the study for efficacy and safety. A follow-up visit will be scheduled 1 week after the end of the 4 week treatment period.