cases with cerebral infarction were treated by infravaseular He-Ne laser irradiation on blood (ILIB).In the treatm ent befor and after,membrane-cholesterol (C)/membrane-phosphatide (P),membran e fluidity (F) and deformability of erythrocyte were dedermined.The result showe d that they were significant difference between the treatment before and after.I LIB true reduce the ratio of membrane-cholesteol/membrane-phosphatide,heighten membrane fluidity and improve deformability of erythrocyte,thus improve blood c irculation and providing oxygen for tissue.At last,the mechanism of laser effect was analysed.