PROBLEM TO BE SOLVED: To provide a composition and a method for treating pathological conditions affecting the skin and/or mucous membrane surface of a subject using an imidazoquinoline compound and a retinoid agent.SOLUTION: Provided is a method for simultaneous administration of an imidazoquinoline compound and a retinoid agent by using a specific composition. The composition comprises both an imidazoquinoline compound at a concentration of 0.1 to 8%(wt/wt) and a retinoid agent at a concentration of 0.001 to 0.1%(wt/wt). A pharmaceutical composition further comprises components selected from salicylic acid, urea, α-hydroxy acid or β-hydroxy acid.SELECTED DRAWING: None【課題】イミダゾキノリン化合物及びレチノイド剤を利用する、対象の皮膚及び/又は粘膜表面に影響を及ぼす病的状態の治療用組成物及び方法を提供。【解決手段】0.1~8%(wt/wt)の濃度のイミダゾキノリン化合物及び0.001~0.1%(wt/wt)の濃度のレチノイド剤の両方を含む組成物。サリチル酸、尿素、α-ヒドロキシ酸又はβ-ヒドロキシ酸から選択した以上の成分を更に含む、医薬組成物。特定の組成物を用いることによる、イミダゾキノリン化合物とレチノイド剤との同時投与方法を提供。【選択図】なし