Abstract: ObjectiveTo study the effect of verapamil and nimo dipine on the level of nitric oxide(NO)in serum of the rats which were poisoned by sulfur mustard,and to inquire into the mechanism initially.MethodsThe rats which were poisoned by sulfur mustard were rescued differently with polysaccharide of spiral alga(PS),reduced glutathione(GSH),verapamil,nimodipine,compound No.1 which was priority to verapamil,compound No.2 which was priority to verapamil,compound No.3 which was priority to nimodipine,compound No.4 which was priority to nimodipine,and established the negative contrast group and the positive contrast group.ResultsThe level of NO of negative contrast group was as same as those of that groups which were rescued differently with verapamil,nimodipine,compound No.1,compound No.2,compound No.3, and compound No.4.The level of NO of positive contrast group was as same as the group that was rescued with GSH.The level of NO of drinking PS group was between those of the negative contrast group and the positive contrast group.ConclusionVerapamil and nimodipine can antagonize the high level of NOinduced by sulfur mustard,the mechanism maybe relate to ver apamil and nimodipine inhibiting the Ca²⁺ to enter cell.