The object of the present invention is to provide a method for suppressing the reduction of isopropyl methylphenol in a pharmaceutical composition for external use. The pharmaceutical composition of the present invention contains isopropyl methylphenol and is contained in a container containing linear low-density polyethylene on the inner wall, and the linear low-density polyethylene has a side chain carbon number of 4 or less, Can suppress the reduction of isopropyl methylphenol.本發明的目的在於提供一種用於抑制外用醫藥組成物中的異丙基甲基苯酚的減量的方法。本發明的醫藥組成物含有異丙基甲基苯酚，收容在內壁包含直鏈狀低密度聚乙烯的容器中，且所述直鏈狀低密度聚乙烯的側鏈的碳數為4以下，可抑制異丙基甲基苯酚的減量。
