Protective effect of inosine against cell death after photochemically induced focal cerebral ischemia was investigated in adult rats.Intraperitoneal injection of inosine was started 24 h before operation and continued till the animals were sacrificed.The TUNEL method and Nissl staining were used to identify apoptosis and necrosis,respectively.TUNEL-positive cells were located in the transitional zone between the necrotic core and normal cortex.The mean maximum area of the necrotic cores and mean number of TUNEL-positive cells 24 h after operation were reduced significantly in the inosine-treated rats when compared with those in the saline-treated control animals.We suggest that inosine can significantly reduce both necrosis and apoptosis following cerebral ischemia induced by photothrombosis in adult rats.