The present invention discloses use of butylidenephthalide (Bdph), a method of using the same, and a method for preparing a pharmaceutical composition containing the same. Because Bdph has the capability of promoting the hair growth and reducing the β-amyloid protein (Aβ) level in nerve cells, the efficacy of improving the health and appearance of a subject can be achieved by administrating an effective amount of Bdph to the subject. Specifically, the Bdph has the efficacy of preventing or treating neurodegenerative diseases such as Alzheimer's disease caused by excessive build up of Aβ in the cells, and as an active ingredient in a topical composition, the Bdph is effective in promoting the hair growth at the site where the Bdph is administered. Furthermore, the method for preparing a pharmaceutical composition containing Bdph comprises preparing the pharmaceutical composition through an organic synthesis reaction, wherein the Bdph is coated with a polymeric material such as F127 by covalent bonding of the polymeric material with the Bdph, thereby achieving the effect of reducing the cytotoxicity of the pharmaceutical composition for an organism.