Androgenetie alopecia(AGA),the most common baldness,is a polygenic hereditary disease of unknown origin.It has been revealed that the pathogenesis of AGA is associated with androgen (especially dihydrotestosterone) and with mental factors.Dermal papilla cells (DPC),which originate from fibroblasts,are mesenehyme cells of hair papilla.DPC express androgen receptors,secrete a variety of cell factors,induce hair follicle regeneration and play an important role in hair follicle cycle.In addition,DPC are concerned with the metabolism of androgen that can stimulate DPC from sensitive hair follicles to secrete soluble cell factors and result in baldness.Therofore,DPC have a close relationship with AGA.