AIM: To explore the role of plasma endothelin (ET) in patients with acute cerebral infarction (ACI) and its change after nimodipine treatment.METHODS:Sixty-six patients with ACI were randomly divided into 2 groups according to blood pressure:hypertension ACI group 35 patients［M 20,F 15;age (65±　s　11) a］ and pure ACI group 31 patients［M 17,F 14; age (62±10) a］.Plasma ET was measured by radioimmunoassay and compared with 27 healthy individuals.Among them,42 patients（hypertension ACI group 25 patients，pure ACI group 17 patients） with ACI were given nimodipine 4 mg, iv,gtt, qd, for 2 wk and measured ET again.　RESULTS:Plasma ET in 2 groups were (144±42) ng*L-1 and (72±35) ng*L-1 respectively, and that were (94±55) ng*L-1 and (60±37) ng*L-1 respectively after treatment with nimodipine, but was still higher than that in healthy individuals (P<0.01).　CONCLUSION: The level of plasma ET was associated with blood pressure and the severity of disease. ET is closely related with ACI. Nimodipine reduces the plasma ET while nerve function default degree is effectively improved.