Chromophores of the skin, especially melanin and exogenous pigments (e.g., tattoos), absorb red ruby laser light (694 nm) comparatively well. Selective photothermolysis of melanin, melanosomes, and tattoo particles theoretically leads to clearing or removing of cutaneous pigmented lesions and tattoos. The excellent cosmetic results after ruby laser treatment are leading to the increasingly widespread use of these costly laser systems. Not only physicians, but also cosmeticians and masseurs work with ruby lasers to remove tattoos and cutaneous pigmented lesions, often without correct dermatological diagnosis. An ever-increasing number of patients present themselves at our department with nevi previously treated with ruby laser. The dimensions and potential sequelae of these treatments are still unknown. Therefore, we present the principles of ruby laser treatment and its indications, side effects, and the main risks.