The present invention relates to the cosmetic use of an essential oil of Laserpitium silex L., as an active agent for preventing and/or treating skin or keratin disorders associated with constriction of the cutaneous capillary circulation. The invention is also directed towards the cosmetic use of the said essential oil as an active agent for improving the appearance of the lips by increasing the size and/or volume and/or thickness of the lips and/or for (re)modelling them and/or making them smooth, and also to a non-therapeutic cosmetic process for caring for the skin and/or keratin fibres.