ABSTRACT
Introduction Phototherapy, the therapeutic application of light in the treatment of diseases has evolved over thousands of years from its origins in Asia. The earliest understanding that photonic energy in visible light could be harnessed through the presence of a photoreactive substance to promote a biological effect in an oxygenated tissue is attributed to the work of Professor von Tappeiner on xanthene derivatives, first published in 1900 (1). This work led to the realization that the destructive skin lesions observed in porphyrias could be attributable to a photodynamic effect.
