Melting stability of these substances is raised in the skin external use medicine which contains the toriterupen acid and the like which is represented in the Ur sole acid, in order to obtain the skin external use medicine which is superior in retention stability, 4- alkyl resorcinol such as 4-n- butyl resorcinol, is made to contain to the skin external use medicine which includes toriterupen acid and the like such as the Ur sole acid benzyl.ウルソール酸に代表されるトリテルペン酸等を含有する皮膚外用剤においてこれらの物質の溶解安定性を高め、保存安定性に優れる皮膚外用剤を得るために、4-n-ブチルレゾルシノールなどの4-アルキルレゾルシノールを、ウルソール酸ベンジルなどのトリテルペン酸等を含む皮膚外用剤に含有させる。
