Medium-wave ultraviolet radiation (UVB) is important in doxycycline phototoxicity.

The phototoxic reaction to doxycycline is provoked by long-wave ultraviolet light (UVA). It was shown by the in vivo mouse tail technique, measuring phototoxic edema, that the addition of medium-wave ultraviolet light (UVB) immediately after, immediately before and especially 24 h before the phototoxic trauma, enhanced the reaction more than could be expected from simple addition, thus demonstrating the importance of photoaugmentation in this process.