Limitations of laser treatment of port-wine stains include failure to produce a satisfactory cosmetic result, scarring and short-term blistering in a high proportion of cases. The cosmetic results and the side effects of the treatment are dependent upon the temperatures generated within the different layers of the skin. By increasing the irradiance of the laser light at the depth of the port-wine capillaries whilst decreasing the irradiance elsewhere, the efficacy of laser therapy should be increased and the incidence and severity of scarring should be reduced. Furthermore, the efficacy of laser therapy should be less dependent upon selective absorption of light by the blood-filled capillaries.