Phototoxicity of oriental medicinal plants: measurement and possible applications.

Phototoxicity can be either harmful and induce adverse skin reactions or beneficial and be used therapeutically as in psoralen and UV-A or photodynamic therapy. Hundreds of medicinal plants are widely used in Asia and Western countries in oriental medicine, yet the phototoxicity of oriental medicinal plants is an understudied area. In this contribution, the authors discuss some methods used to measure the phototoxicity of plants and give an overview of the results of their previous and ongoing studies into the phototoxicity of medicinal plants. The authors argue that because they found that more than a quarter of oriental medicinal plants can be phototoxic, such research is helpful for dermatologists and that active phototoxic components extracted from oriental medicinal plants may be used therapeutically.