It is well known that light, as a fundamental form of energy, plays an important role in all life processes. The main type is sunlight, which is available in a specific amount depending on the place and the moment during the year. Because of this, people have developed strategies and methods to use as effectively as possible the properties of light, visible and invisible, to stay healthy or get healed. In the article we present and discuss the effects of light energy on the body. Many methods are based on real physical properties and give good results; some are dubious and rely essentially on the patients' ability to believe.

A new era for light therapy began when the laser was invented in 1960. The light emitting from this artificial source has properties that can be precisely adapted to the intended use. The combination of artificial intelligence and the precision of laser light makes it possible to create new instruments at the disposal of doctors. We describe some therapies by means of light, which were not imaginable before.