BACKGROUND: Selenium is one of necessary microelement of human body. It acts as the active center of selenium-contained enzyme with antioxidant function, which can clean up internal free radical, effectively catalyze harmful perhydride deoxidizing into innocuous hydroxyl compound,reinforce immunity of human body, prevent and cure cardio-cerebrovascular diseases and cancer.OBJECTIVE: To provide evidence for preventing and treating cardiocerebrovascular diseases via comparison of blood selenium content between patients and healthy persons.DESIGN: Case-control analysis.SETTING: Dalian Railway Medical School, Dalian Railway Hospital, Department of Applied Chemistry, Dalian Railway College.PARTICIPANTS: Totally 319 blood samples (169 males, 150 females)were collected from patients with cardio-cerebrovascular diseases from Dalian Railway Hospital from March 2000 to May 2001. Among them,there were 164 with hypertension, 97 with coronary atherosclerotic heart disease (CAHD), 41 with cardiac dysrhythmia and 17 with cerebral vascular accident. 300 healthy patients (159 males and 141 females) were in the healthy group.METHODS: The blood selenium content of patients with cardio-cerebrovascular diseases was detected with neopolarography.MAIN OUTCOME MEASURES: ①Total level of blood selenium of testees of the two groups. ②Comparison of level of blood selenium between males and females. ③Comparison of level of blood selenium of patients with different diseases.RESULTS: A total of 619 testees were involved in the result analysis. ①The total level of blood selenium of the patient group was lower than that of the healthy group [(114.0±52.5), (146.5±51.0) μg/L,P ＜ 0.001],which was only 76% of that of the healthy persons. ②Content of blood selenium of males and females was normal distribution. There was insignificant difference between males and females (P ＞ 0.10), but the level of blood selenium in females was slightly higher than that of males. ③The levels of blood selenium of patients with hypertension, CAHD, cardiac dysrhythmia were 82.7%, 68.6% and 66.0% of that of healthy persons, respectively, but the difference between males and females was insignificant(P ＞ 0.10). The level of blood selenium of patients with cerebrovascular accident (CVA) was the lowest, (84.4±28.9)μg/L, which was 57.6% of healthy persons.CONCLUSION: The content of blood selenium of patients with cardiocerebrovascular diseases is lower than that of healthy persons. Organic selenium and inorganic selenium should be supplemented moderately.