PROBLEM TO BE SOLVED: To provide a melanin synthesis inhibitor, a whitening agent, an antioxidant, an antiaging agent and an antimicrobial agent which have high safety since they are derived from natural stocks, and the bark extract of a bamboo shoot included therein.SOLUTION: The bark extract of a bamboo shoot is obtained by performing extraction from the ground product or powder of the bark of a bamboo shoot using a solvent such as methanol and ethanol, and has all or at least one or more of a melanin synthesis inhibitory action, a whitening action, an antioxidant action, an antiaging action and an antimicrobial action. Further, the melanin synthesis inhibitor, whitening agent, antioxidant, antiaging agent or antimicrobial agent includes the bark extract of a bamboo shoot as an active constituent.
