The use of an effective amount of at least one nitric oxide synthase
inhibitor in a cosmetic composition or for making a pharmaceutical
composition is disclosed, said inhibitor or pharmaceutical composition
being intended to reduce the skin irritant effect of topically applied
cosmetic or pharmaceutical substances. A cosmetic or pharmaceutical
composition containing an effective amount of at least one nitric oxide
synthase inhibitor, and a cosmetic treatment method using said cosmetic
composition, are also disclosed.