The appliance of a therapeutic laser also known as soft laser has gained wider scope in the latest years. The main characteristics of the laser radiation, namely its monochromatic and coherent nature render the photochemic activity selecive especially on the intracelluar level, stimulating the dynamics of the oxido-reductive changes in a cell. The action of the laser beam upon living tissue depends on the power of the used laser as well as upon the physical properties of the object itself i.e. its optical, mechanical, chemical properties. The use of a high powered laser causes a big rise in the temperature and prescure inside tissue which leads to denaturation of protein and than to evaporation and destruction of the cell. It is possible to gain quite diffrent effects using a soft /or therapeutic/ laser which in the course of stimulating the biological changes in a cell causes its regeneration and not its degradation. There exist three main phenomena on the level of the radiation emition. These are absorption, reflection and penetration. The most important from the medical point of view are penetration and absorption, for the direct biological changes depend upon these very parameters. The action of the laser beam upon tissue in fig. 1.