Tattooing is an ancient art and is still widely practiced all over the world. Since the biocompatibility of tattoo dyes has not been well researched, we studied the toxicity of a commercial tattoo ink, commonly used in tattoo lab and esthetic centers, on human fibroblasts. To test cell viability, MTT assays were carried out and scanning electron microscopy to visualize changes in the cell surface after the dye exposure was performed. A possible influence of the pigment on the expression of procollagen alpha1 type I protein was visualized by western blotting analysis. The results showed a reduction in cell viability, and electron microscopy demonstrated an unmodified cell surface completely covered by pigment particles. Western blotting analysis demonstrated a clear interference of the pigment on the expression of procollagen alpha1 type I protein. These data demonstrated that the commercial tattoo dye has a time-dependent effect on protein expression. A possible connection of the influence of the tattoo ink with clinical effects is discussed.