A favorable effect of laser therapy in rheumatic diseases was demonstrated in a previous paper [9] but it was not possible to estimate whether this benefit was due to an antiinflammatory, analgesic or decontracturant effect. In this work the effect of laser therapy was tested on an experimental inflammation in rats. Laser irradiation reduced the volume of the inflammation during 6 days of treatment more than 85% and prevented the appearance of necrosis. In the control group, the reduction of inflammation was of only 22.86%, the difference vs. the treated group being significant for p = 0.00009, and eight rats of the ten developed local necrosis.