Historically, the most used substance in treatment is hydroquinone, in concentrations ranging from 2% to 4%, or higher inassociation with sunscreens. The classic formulation of Kligman contained hydroquinone, tretinoin and a corticosteroid with lowactivity. Concentrations of hydroquinone up to 8% -10% have been created to lighten the skin of black race individuals, but theyturned out to be very dangerous for the human health. Also due to its indiscriminate use and to its CARCENOGIC effects,hydroquinone is no longer available and has been banned by the European Union (The 24th Directive 2000/6/EC).