With increased popularity of decorative tattoos, awareness of tattoo-based dermatological complications has been raised. Health issues include a broad spectrum dominated by allergies and infections. To examine the etiopathology and prognose the outcome of an appropriate therapy, a non-invasive intravital diagnostic approach is indicated. The present pilot study introduces multiphoton tomography equipped with fluorescence lifetime imaging as a diagnostic technique to examine the morphological and metabolic status of tattooed human skin at patient's bedside. The distributing course of tattoo particles can be visualised over time. By providing optical biopsies, inflammation-based alterations in freshly tattooed skin and tattoo complications can be analysed. The study concludes that multiphoton tomography combined with fluorescence lifetime imaging is a suitable technique for in vivo visualisation of tattoo pigments as well as for the assessment of quantitative and qualitative skin changes after injection of tattoo ink into human skin.