A substance is disclosed that can inhibit the activity of aromatase (an enzyme capable of converting androgen into estrogen) to thereby effectively treat and/or prevent a sex hormone-dependent disease such as breast cancer occurring in a female person after menopause, as well as a climacteric disorder in a male person and metabolic syndrome caused by the accumulation of a visceral fat. Specifically, a therapeutic and/or prophylactic agent for a sex hormone-dependent disease comprises at least one herbal extract selected from the group consisting of “Kokeiten,” prunella spike, sweet hydrangea leaf, milk thistle, a jasmine tea, “Bokusoku,” “Tencha,” “Karensou,” “Youbaihi,” French maritime pine, betel palm, asparagus, “Rouro,” “Ryoukyou,” rooibos tea, rhubarb, pu-erh tea, green tea, “Ougon,” St. John's wort, licorice, “Senrikou,” wintergreen, “Kashi,” “Yagotou,” polygnum root, barrenwort, guarana, “Ouhi,” Argy's wormwood, sticky rehmannia, Japanese cornel, Asiasarum root, cinnamon, peony root, pine needle and amla fruit.
