In order to study the interaction between the laser and biological tissues, we realized an experimental "in vivo" model using 12 Wistar male adult rats (mean b.w. 300 gr.). On the animals, during general anesthesia and after an accurate shearing of the back, we performed a cutaneous lozenge in order to value the characteristics and the possibilities of a last generation laser. It concerns of a CO2 laser (EASY LASER SP5, CLASS IV F.D.A.) with the possibility of employing of different variables. During this study were evaluated the most interesting variables: frequency, power and duty cycle. Among the variables we identified the frequency of the application range of the superpulse effect and the selective photothermolysis. The histological and morphological studies performed on the cutaneous specimens after laser treatment, showed that the correct application of this kind of laser can be an effective help for the surgeon during clinical practice.