Laser therapy or Laser Phototherapy is a method where light from a laser is applied to tissue (or cells in culture) in order to influence cell or tissue functions with such low light intensity that heating is negligable. The effects achieved are hence not due to heating but to photochemical or photobiologic reactions like the effect of light in plants. The lasers used are normally called therapeutic lasers or medical lasers.
This is in contrast to the use of lasers in surgery and for esthetic purpose where strong lasers are used and where the biologic effects (cutting, evaporating, coagulating) are based on heat development from the absorption of strong light, i.e. burning glass effect.