<qa>  What is the goal of this study?The goal of this study is to find an effective and well-tolerated medical therapy for itching due to liver disease. Persons with primary biliary cirrhosis or chronic hepatitis C are currently being enrolled in the study. Persons participating in the study are given sertraline, a medication which is also often used for depression,to treat their itching. The dose is gradually increased as the effect on itching and any other potential side effects are carefully monitored. 