Objective To determine whether rapid and delayed tolerance to focal cerebral ischemia can be induced by pretreatment with single electroacupuncture (EA) at the Baihui acupoint in rats. Methods Forty-eight healthy male SD rats weighing 280-320 g were randomly divided into 6 equal groups with 8 animals in each group: (1) control group received no pretreatment before focal cerebral ischemia; (2) electroacupuncture group was further divided into 5 groups in which EA was performed at Baihui acupoint and electric stimulation was maintained for30min0.5 h(EAl),1 h(EA2),2 h(EA3),3 h(EA4) or 24 h(EA5) before focal cerebral ischemia. The animals were anesthetized with isoflurane and spontaneous respiration was maintained. Middle cerebral artery occlusion (MCAO) was performed using a nylon thread with a rounded tip inserted into internal carotid artery and thread cranially until resistance was felt. MCAO was maintained for 2 h, then the nylon thread was withdrawn to allow reperfusion . After MCAO the animals were observed for 24 h for neurological deficits which were assessed by a 0-5 grade scoring system (0 = no deficit, 5 = death) . The animals were then sacrificed and brain was immediately removed for estimation for the size of cerebral infarction. Results There were significantly less neurological deficits and the size of infarction was smaller in group EA3 and EA5 than those in control group. There were no significant differences in neurological deficits and size of infarction between group EA1,EA2,EA4 and control group. Conclusion Pretreatment with single electroacupuncture stimulation for 30 min at Baihui acupoint can induce rapid and delayed tolerance to focal cerebral ischemia. Rapid tolerance develops 2 h after pretreatment while delayed tolerance develops 24 h after pretreatment.