The present invention relates to a method of promoting skin rejuvenation in a subject. The method comprises administering to the subject an effective amount of a cellular extract of epithelial or mesenchymal stem/progenitor cells isolated from the amniotic membrane of the umbilical cord, wherein the cellular extract contains growth factors and peptides and is in the form of a supernatant into which the epithelial or mesenchymal stem/progenitor cells secrete the growth factors and peptides.