1. Purpose This studies the regulatory effect of cytokine production in Soyangin patients with cerebral infarction by Yangkyuksanhwatang. 2 Method ELISA 3. Result & Conclusion Yangkyuksanhwatang(YST) is a prescription for the cerebral infarction (CI) patients of Soyangin according to Sasang constitution philosophy. Soyangin patients with CI were treated with YST during the acute stage. Clinical signs of CI disappeared markedly in about 2 to 4 weeks after oral administration of YST in all patients. The mean interleukin (IL)-2 plasma levels were slightly lower in the patients with CI than in the normal groups, whereas the mean IL-4, IL-6 and IgE levels were significantly higher in the patients. There were no significant differences in interferon- ${gamma}$ (IFN- ${gamma}$ ) levels between the groups. Serum IFN- ${gamma}$ and IL-2 levels derived from T helper (Th)1 cells were elevated significantly in the patients with CI by YST administration. Significant reduced plasma levels of IL-4 and IL-6 derived from Th2 cells and IgE were observed in the patients treated with YST. During the period of YST administration, there were no other adverse effects. The data indicate that YST has a good CI treatment effect, and that its action may be due to regulation of cytokine production.