PROBLEM TO BE SOLVED: To provide cosmetics, pharmaceuticals, quasi drugs, and food and drinks for treating, improving, and preventing diseases or pathologies, such as pigmentation or cancer associated with enhancement of Wnt/&bgr-catenin signal by finding out a novel factor which has Wnt expression inhibiting action and is stable in the living body.SOLUTION: The invention provides Wnt expression inhibitor or melanin synthesis inhibitor which contains Phalaenopsis aphrodite extract as an active ingredient, and cosmetics, pharmaceuticals, quasi drugs, or food and drinks containing the inhibitor.