Abstract: A device for treating skin, the gums, a tooth, or an internal organ by a laser pulse source for generating laser pulses with a pulse duration which is preferably in the femtosecond range, and an optical path for directing the laser pulses from the laser pulse source for the surface of the skin, gums, tooth or internal organ. The laser pulses are directed onto the surface of the skin, gums, tooth or the internal organ in such a way that the pulses are focused in the skin, in the gums, in the tooth or in the internal organ and cause a laser-induced optical breakdown below the surface of the respective skin, gums, tooth or internal organ, whereat the laser pulses have a larger cross-sectional area at the surface of the skin, of the gums, the tooth or of the internal organ than at the location of the laser-induced optical breakdown.