Light therapy or phototherapy involves exposure to daylight or a specific wavelength of light using lasers, light-emitting diodes, fluorescent lamps, dicron lamps, or high-energy, full-spectrum lamps, usually controlled by various devices. Light is prescribed for a period of time and in some cases, at a specific time of day.

Medical applications of light therapy include pain control, accelerating wound healing, hair growth, improving blood and circulatory properties, and diseases and disorders associated with the sinuses. Many of these applications use low-power laser therapy and red light therapy in the range of 620–660 nm.