The present invention provides a substance which can modulate expression of a Period gene effectively and with a wide range of application. Provided is an expression modulator for the Period gene comprising, as an active ingredient, one or more selected from the group consisting of arnica extract, nuphar extract, black tea extract, Zanthoxylum extract, juniper oil, cedar oil, lavender oil, clove bud oil, cypress oil, rose oil, ylang-ylang oil, galbanum oil, petitgrain oil, pepper oil, thyme oil, basil oil, and beta-caryophyllene.本發明之課題在於提供一種可應用於廣泛用途且有效地調節Bmal基因表現之物質。本發明係關於一種Bmal基因表現調節劑，其含有選自由扁柏萃取物、綠藻萃取物、蛇麻草萃取物、山椒萃取物、杜松子油、薰衣草油、尤加利油、乳香、絲柏油、玫瑰草油、松針油、玫瑰油、伊蘭油、欖香脂油、苦橙葉油、胡椒油、麝香草油及洋甘菊油所組成之群中之1種以上作為有效成分。
