Extracts of St John's wort (Hypericum perforatum) are widely used in the treatment of depressive disorders,1 The naphtodianthrone hypericin is one of the active pharmacologic substances of H perforatum. It is known that hypericin may cause a severe photodermatitis when higher amounts of St John's wort are ingested by animals. In a recent phase 1 study, HIV-infected patients were treated intravenously with high doses of de novo synthesized pure hypericin; almost all of these patients experienced phototoxic effects.2 In contrast, little information exists on the photosensitizing capacity of Hypericum extracts in doses used for the treatment of depressive disorders. The aim of the present prospective randomized study was to investigate the effect of such an extract (LI 160; Lichtwer Pharma, Berlin, Germany) on skin sensitivity to UV-B, UV-A, visible light, and solar-simulated radiation.
Schempp CM, Müller K, Winghofer B, Schulte-Mönting J, Simon JC. Single-Dose and Steady-State Administration of Hypericum perforatum Extract (St John's Wort) Does Not Influence Skin Sensitivity to UV Radiation, Visible Light, and Solar-Simulated Radiation. Arch Dermatol. 2001;137(4):512-513. doi: