The effects of 70% methanolic extract (CC-ext) from Cinnamomi Cortex on acute and chronic inflammation were investigated.CC-ext inhibited the rise in vascular permeability induced by acetic acid and the increase of paw edema induced by carrageenin in mice. It was ineffective on edema derived by histamine or bradykinin, and exhibited only weak inhibitory effect on the edema derived by serotonin. CC-ext also showed inhibitory effects on the prekallikrein enzyme activity and ear edema induced by arachidonic acid. It also had an inhibitory effect on cotton pellet-induced granuloma but showed no atrophying action against the adrenal or thymus glands. Little effect was shown on secondary lesions in the development of adjuvant-induced arthritis (the arthritis reappeared from 11 to 27d after injection of the adjuvant). These results suggest that some active component having an inhibitory effect on acute inflammation is contained in Cinnamomi Cortex.