Objectives : In order to investigate the effect of Bobitang on SD rats with deteriorated immunity caused by methotrexate. Methods : The test sample were dosed once a day for 14 days by gastric gavage at a dosage 1,000, 500 and $250mg/kg/10m{ell}$ from 2 days after last MTX-dosing, and the changes on body weight and gains, spleen weight and total blood leukocyte numbers, total lymphocyte numbers, the percentage of B-cell, T-cell, CD3+CD4+ T-cell, CD3+CD8+ T-cell and CD4+/CD8+ T-cell ratios in the blood and spleen were observed. Results : The changes on body weight gains, the spleen weight, the total blood leukocyte numbers, the total lymphocyte numbers in the blood and spleen, the ratio of T-cell in the blood and spleen, the ratio of CD3+CD4+ T-cell in the blood and spleen were increased significantly in BBT Extracts groups as compared with control group. The ratio of B-cell in the blood and spleen was not increased significantly in BBT Extracts groups as compared with control group. The percentage of CD3+CD8+ T-cell in the blood and spleen was decreased significantly in BBT Extracts groups as compared with control group. The ratio of CD4+/CD8+ T-cell in blood and spleen was increased significantly in BBT Extracts group as compared with control group. Conclusions : According to the above results, Bobi-Tang has an effect of increasing immune responses on SD rats with deteriorated immunity caused by methotrexate.