A pharmaceutical agent containing sap of Betula platyphylla Sukatchev var. japonica Hara as an effective ingredient and its use are provided to promote production of profilaggrin and filaggrin which are natural moisturizing factors, involucrin functioning as a barrier protecting against water loss and cholesterol capable of inhibiting water loss, and to restore the cells. The pharmaceutical agent for promoting production of profilaggrin, filaggrin, involucrin and cholesterol, and restoring the cells contains sap of Betula platyphylla Sukatchev var. japonica Hara which is prepared by collecting sap from the stem of Betula platyphylla Sukatchev var. japonica Hara, heating the sap at 95 deg.C for 10 minutes, cooling and filtering the heated sap, and standing the sap at 5 deg.C for 3 days to remove sediment or precipitates.천연물 유래의 신규한 프로필라그린 또는 필라그린 생산촉진제, 인볼루크린 생산촉진제, 콜레스테롤 생산촉진제 및 세포부활제를 제공하는 것이다.자작나무(Betula platyphylla Sukatchev var. japonica Hara) 수액을 유효성분으로 하는, 프로필라그린 또는 필라그린 생산촉진제, 인볼루크린 생산촉진제, 콜레스테롤 생산촉진제 및 세포부활제이다.
