RESUMEN
First of all some general concepts are given on phototoxic activity of pharmaceutical products which full fill the structural characteristics required to decompose by light and to cause biological damage, either themselves, their photoproducts or the products of their metabolism. These considerations are important due to the fact that this field of research is fairly new. Next, a review is given on recent research carried out in this laboratory on the photochemistry and phototoxicity of fibric acid and their derivatives and finally a refc5r cview is made as well on the photochemistry and phototoxicity of antibacterial quinolones. Mechanisms are postulated for the photochemical decomposition of the substances investigated and possible mechanism for the in vitro activity at cellular level are also presented