This study will examine the effect of S-adenosyl methionine (SAMe) on itching and fatigue in patients with primary biliary cirrhosis, a disease of the small bile ducts in the liver. Ursodiol, the only currently available treatment for biliary cirrhosis, does not cure the disease, and many people continue to have symptoms or liver test abnormalities despite treatment. SAMe is a naturally occurring substance found in most cells of the body. The highest levels of the substance are produced by the liver, where it helps to rid the body of toxins and breakdown products of metabolism. Studies in Europe suggest that SAMe may help to: 1) decrease the fatigue and itching that are common in persons with liver problems, and 2) decrease levels of liver enzymes in the blood, suggesting that it may decrease the amount of liver injury.