The study was performed to investigate the effect of Houttuyniae herba Aqua- acupuncture on immune responses in irradiated rats. The results are as follows; 1. In the assay of peripheral lymphocytes, Houttuyniae herba aqua-acupuncture showed protective effect on peripheral lymphocytes from irradiation. 2. In the assay of $CD_4;&;CD_8$ T lymphocytes, Houttuyniae herba aqua-acupuncture showed pretective effect on $CD_4;and;CD_8$ T lymphocytes from irradiation with no stastistical significance. 3. In the assay of spleen lymphocytes, Houttuyniae herba aqua-acupuncture showed pretective effect on lymphocytes from irradiation with stastistical significance. 4. In the assay of spleen $CD_4$ T lymphocytes, Houttuyniae herba aqua-acupuncture showed pretective effect on $CD_4$ T lymphocytes from irradiatian with stastistical significance. 5. In the study of $CD_8$ T lymphocytes, Houttuyniae herba aqua-acupuncture showed pretective effect on $CD_4$ T lymphocytes from irradiation with no stastistical significance These results show that Houttuyniae herba aqua-acupuncture is an effective therapy upon immune deficiency induced by irradiation.