Effects of acupuncture stimulation on the lumbar area and those of electrical stimulation of the sciatic nerve on blood flow to the sciatic nerve were studied using laser Doppler flowmetry in anesthetized rats. Changes in the nerve blood flow induced by acupuncture stimulation were not similar. Half of the blood flow responses correlated with changes in arterial blood pressure. In the other half, responses did not always agree with changes in arterial blood pressure. Electrical stimulation was administered to the sciatic nerve contralateral or ipsilateral to the blood flow measurement site. Electrical stimulation of the ipsilateral side increased nerve blood flow without increasing arterial pressure. Administraton of atropine slightly diminished the response. Contralateral nerve stimulation, changes in nerve blood flow were not accompanied by arterial pressure changes. These results suggested that nerve blood flow may increase without increment of the arterial pressure in response to certain types of acupuncture stimulation.