Herbal medicine, Herba Taraxaci (Tarazacum mongolicum Hand.-Mazz.), was administered to mice with Behcet's disease (BD)-like symptoms induced by herpes simplex virus (HSV). BD is a chronic recurrent inflammatory disease. Herba Taraxaci (6 mg) was administered alone or in combination with 2 microg of colchicine to BD-like mice. Colchicine is a drug that is widely used as a medication for BD patients. The water extracts of Herba Taraxaci were administered orally once per day for 20 days. Eighty percent (8 of 10) of mice treated with Herba Taraxaci combined with colchicine showed improvement in mucocutaneous symptoms compared to 0% (0 of 10) of the nontreated group and 30% (3 of 10) treated with colchicine alone. Cytokine expression in spleen tissue collected from treated mice was analyzed by RT-PCR and FACS. Treatment with Herba Taraxaci induced IL-4 mRNA, and spleen from mice receiving the combined treatment (Herba Taraxaci and colchicines) showed an increased number of splenocytes staining with anti-IL-10 (46.8+/-6.80) compared to Herba Taraxaci (35.4+/-2.17) (p<0.05) or colchicine alone (26.2+/-4.47) (p<0.001). These results suggest that the Herba Taraxaci may be an effective complementary agent in the treatment of BD.