The present invention discloses a novel use of bakuchiol or an extract containing bakuchiol in preventing or treating a woman suffering osteoporosis. An embodiment of this novel use is a pharmaceutical composition containing bakuchiol or an extract containing bakuchiol, which can be in the dosage forms of topical use, oral administration, injection or sustained release. The present invention also discloses a novel use of bakuchiol or an extract containing bakuchiol in preventing or treating a woman suffering breast cancer.