Abstract:Mieyanling has an antipyretie effect on the fever of animals caused by yeast or TAB vaccine. The hypothermal effect of Mieyanling on the temperature of normal mice and rats was also observed. The ED50 of antipyretio and hypothermal action of this drug in mice was 20g/kg and 50g/kg respectively. There was a CNS depressive effect when Mieyanling was administered 60g/kg orally to mice.