A method for the anti-senescence of and/or rejuvenating a stem cell is provided. The method comprising treating the stem cell with trans-cinnamaldehyde (TC). A kit is also provided. The kit comprising (1) a first part, comprising a stem cell; (2) a second part, comprising TC; and (3) a culture medium of the stem cell, placed in at least one of the first part, the second part, and a third part. In addition, a method for stem cell therapy is provided. The method comprising administering to a subject in need an effective amount of a stem cell, wherein the stem cell has been treated with TC before being administered.