To study FAO's effect on injury of hippocampal CA3 neurons of restrained rats in stress.In stress group,the number of rat hippocampal CA3 neurons decreased,the length of apical dendrite was shortened,some cells were swelling,other cells were shrinking,some Nissl bodies were blurry,other Nissl bodies were disappear.In group,the neurons have no significantly change like in group.The FAO could prevent the hippocampal CA3 neurons of restrained stress rat from injury.