The invention proposes to use a plant material derived from Marrubium vulgare for a non-therapeutic cosmetic treatment for tightening skin pores, said plant material comprising an effective amount of Forsythoside B as the active molecule. The plant material is preferably constituted of a cellular extract of dedifferentiated plant cells freed from cellular debris. This treatment is particularly intended for refining skin grain and/or for treating skin with an oily tendency.
