Osthole, a main active constituent from Cnidium mon nieri (L.) Cusson, has been considered therapeutic agent in the treatment of ischemic stroke.This study was designed to investi gate the effect of osthole on permanent middle cerebral artery oc clusion (MCAO) in rats.Osthole was administrated by gavage to the normal and the MCAO rats.Rats were assessed for neurologi cal deficit after 24 h following MCAO, then their brains were e valuated to determine the infarct area, and the mRNA and pro tein levels of some inflammatory factors were detected.It was found that MCAO animals pre-treated with osthole for 7 d showed significant improvement in all neurological tests compared with vehicle-treated MCAO groups.