Twenty patients with hepatitis B e antigen (HBeAg) -positive chronic hepatitis, who received 40 mg of prednisolone per day for three weeks followed by withdrawal, were studied for changes in alanine aminotransferase (ALT), triiodothyronine (T3), thyroxine (T4), and hepatitis B virus DNA polymerase (HBV-DNAp) levels determined before and during prednisolone treatment and after its withdrawal. A decreased HBV-DNAp level of less than 100 cpm/ml three to five weeks after withdrawal was considered a sign of efficacy and was shown in 10 patients (50%). Significant differences were found between ALT levels, between T3 levels, and between the T3/T4 ratios assayed in the third and fourth weeks in total (P less than 0.02) and in the group in which efficacy was demonstrated (P less than 0.01). The T3/T4 ratio in the third week in the effectively treated group was significantly less than that in the noneffectively treated group (P less than 0.05). Prednisolone withdrawal effective for HBV-DNAp was shown in the patients with a decreased T3 level and the T3/T4 ratio at the third week and an increase in the ATL level after the withdrawal. The ALT level increased after the T3 level decreased. Changes in the T3 level or the T3/T4 ratio represent a marker for effectiveness of prednisolone withdrawal and for determination of combination therapy after steroid withdrawal.