A short pulse duration ruby laser with pulse duration of 200-400 microsec, was applied for treatment of nevus spilus. Nine out of twenty three cases of nevus spilus (40%) were effective after one or several shot. Six cases (26%) were not effective after one shot and 8 cases (35%) were not effective even after several shots,although the exanthema became lighter before irradiation. Histlogically the epidermal basal cells were damaged and “craster-like degeneration” was also observed in the incontinent areas in the upper dermis.
