To investigate the effects of ESWTT on rheumatoid arthritis in collagen-induced arthritis mice model, the animals were orally administrated with the extract following by analyzing the changes of lymphocyte composition in spleen with flow cytometry. These results suggest as follows; 1. ESWTT decreased the total cell number of spleen at 400 and 200 mg/kg about 41% and 32%, respectively. 2. ESWTT reduced the number of CD19+ cells in spleen at 400 and 200 mg/kg about 51% and 46%, respectively. 3. ESWTT down-regulated the number spleen CD3+ cells approximately 26% at 400 mg/kg-treated group. 4. ESWTT decreased the number of CD3+/CD69+ cells in spleen at 400 and 200 mg/kg about 79% and 76%, respectively. 5. ESWTT reduced the number of CD4+ and CD8+ cells in spleen, however, the results were not significant. 6. ESWTT decreased the number of CD4+/CD25+ cells in spleen at 400 and 200 mg/kg about 60% and 56%, respectively. Taken together these results, ESWTT has an efficacy on rheumatoid arthritis through inhibiting the proliferation of lymphocytes such as B and T cells.