ABSTRACT— We conducted a clinical trial to study the effects of a 10-week course of prednisone therapy and its withdrawal on serum aminotransferase levels and on hepatitis B virus (HBV) markers in patients with hepatitis B surface antigen (HBsAg) positive chronic active hepatitis (CAH-B). Eighteen patients with CAH-B were treated with prednisone, while another 18 patients matched for age, sex, race and sexual preference were followed simultaneously without treatment for the same duration. Nine of 18 prednisone-treated patients became transiently DNA polymerase positive. All nine patients developed a transient rise in serum alanine aminotransferase (ALT) levels of greater than 300 U/L above baseline values, which was associated with a drop in HBsAg levels from a mean of 186 μg/ml prior to therapy to 92 μg/ml at 6 months following treatment. Six of these patients developed fatigue, anorexia and dark urine, and four also developed either ascites or hemorrhage from esophageal varices, which was accompanied by hepatic encephalopathy. All six of these patients had histologic evidence of CAH with cirrhosis. In comparison, none of the control, untreated patients with CAH-B had any change in either HBV markers or serum ALT levels. Therefore, even a short course of prednisone in patients with CAH-B with cirrhosis is detrimental and its use should be discouraged.