Abstract: Photomodulation,also known as photobiomodulation,has been described as a process that modifies cell activity by using laser,light-emitting diode (LED) and other light sources without thermal effect.The underlying mechanisms for photomodulation are believed to be the activation of energy metabolic switches in mitochondria followed by the increase in cell proliferation and migration as well as the modulation of cytokine and inflammatory mediator levels.This treatment modality employs low-energy and narrow-band light sources with specific pulse sequences and durations,and has won more and more attention in the field of dermatology.It has been used not only in rejuvenation,wound healing,treatment of inflammatory diseases and hair loss,but also in the prevention of postinflammatory hyperpigmentation,sunburn and scarring.