Lymphocyte proliferation of splenocytes induced by concanavalin A(Con A) and the induction of IL-2 production test were used to study the effects of acupuncture on immunomodulation by stimulation of Zusanli(ST 36) and Lanwei (Extra 33) points of the rat's left leg.It was observed that the lymphocyte proliferation of splenocytes was increased in EA groups of 3 days (p<0.05)

5 days (p <0.001) and 7 days (P<0.05).The parabolical curve could be found by currilinear regression (R2 =0.9901).EA groups of 3 days and 5 days had a significantly increased induction of IL-2 production (P<0.05).These results will be helpful to choose an optimal time for clinical treatment