Abstract: OBJECTIVE To investigate the mechanism, risk factors and management of valproate-induced hyperammonemic encephalopathy(VHE), provide suggestions for clinical medication. METHODS Clinical pharmacists had involved the treatment of a case of VHE. RESULTS While valproate was combined with some drugs, such as phenobarbital or topiramate, the risk of high blood ammonia encephalopathy may be enhanced. CONCLUSION It is necessary to avoid the usage of valproate combined with phenobarbital clinically, meanwhile to timely monitor ammonia of the patients who are taking valproate due to the?decreased consciousness.