PROBLEM TO BE SOLVED : To inhibit the generation of an oxidant in a liquid pharmaceutical syringe preparation containing teriparatide. SOLUTION : This invention relates to a method of inhibiting the generation of an oxidant in a liquid pharmaceutical syringe preparation containing component 1 during its storage, by shielding the preparation from light. The oxidant is a teriparatide oxidant or an acetate thereof in which a 18-th methionine residue from an N terminal of teriparatide is sulfoxidized. The component 1 : a teriparatide oxidant or an acetate thereof. SELECTED DRAWING : None COPYRIGHT : (C)2019, JPO&INPIT