This study is a 24-week multicenter, randomized, double-blind control trial with ursodeoxycholic acid (UDCA) in patients with chronic hepatitis C in Japan. The primary objectives of this study are to verify the superiority of efficacy of UDCA 600 or 900mg/day to that of 150mg/day and the safety of UDCA treatment.

This study is a 24-week multicenter, randomized, double-blind control trial with ursodeoxycholic acid (UDCA) in patients with chronic hepatitis C in Japan. The primary objectives of this study are to verify the superiority of efficacy of UDCA 600 or 900mg/day to that of 150mg/day and the safety of UDCA treatment. The primary endpoint was percent changes of serum alanine aminotransferase(ALT) levels at 24-week of administration compared to pre-administration levels and secondary endpoints, serum aspartate aminotransferase(AST) and gamma-glutamyltranspeptidase(gamma-GTP) levels. Further, changes of bile acid composition and HCV-RNA levels at 24-week of administration were examined.

Inclusion Criteria:

1. Subject must have a clinical diagnosis to apply the conservative medication for chronic hepatitis C.
2. Serum alanine aminotransferase levels measured at 4-week before the initiation of treatment must be over 61 IU/mL.
3. Subject's age must be 20 years or older.

Exclusion Criteria:

1. Subject who received a treatment of antiviral agents (interferon) within 20 weeks before the start of 8-week observation period
2. Subject who received a treatment of corticosteroids, immunosuppressive drugs, glycyrrhizic acid, cholestyramine or other drugs which could interfere with hepatic function during 8-week observation period.
3. Subject with decompensated cirrhosis
4. Subject infecting with other hepatic virus
5. Subject receiving a treatment for autoimmune disease, alcohol or drug-induced hepatic disorder, neoplasia, hepato-cholangiolar disease, fulminant hepatitis or peptic ulcer
6. Subject who require hospitalization for complications of the heart, kidney or pancreas
7. Pregnancy
8. Alcoholics
9. Alcohol intake more than 27 ml/day
10. Subject who involved in other clinical trial within 4 weeks before the start of observation period
11. Subject with a history of sensitivity to ursodeoxycholic acid or bile acid-products

The reported adverse event data were collected for 24 weeks.