Effect of Kanzo-bushi-to (TJS-038), one of the Japanese Kampo medicines originating from traditional Chinese herbal medicine, on the activity of a clone of burn-associated CD8+ suppressor T cells (T6S cells) was investigated. The suppressor cell activity of T6S cells in the mixed lymphocyte-tumor cell reaction (MLTR) was not changed when various concentrations of TJS-038 were added to the MLTR. The suppressor cell activity of T6S cells was greatly inhibited by CD3+ CD4+ CD28+ TCR alpha/beta+ Vicia villosa lectin-adherent cells (TJS cells) purified from spleen cells of mice treated with TJS-038 at an oral dose of 50 mg/kg. The suppressor cell activity of T6S cells was not demonstrated in the MLTR assay when anti-IL-4 monoclonal antibody was added. Also the production of IL-4 from T6S cells was not detected, when they were co-cultured with TJS cells. These results suggest that TJS-038 stimulates the generation of contrasuppressor T cells (TJS cells) that inhibit the suppressor cell activity of T6S cells and the production of IL-4 from T6S cells.