Cosmetic active agent obtained from Alisma plantago aquaticarhizome, is claimed, where the active agent is a hydrolyzate of Alisma plantago aquaticarhizome comprising peptides having a molecular weight of less than 2000 Da. ACTIVITY : Dermatological; Immunostimulant. MECHANISM OF ACTION : Thrombopoietin receptor stimulator; Toll-like receptor-2 (TLR-2) stimulator. The ability of cosmetic active agent to express TLR-2 was tested in normal human keratinocytes. The result showed that cosmetic active agent expressing TLR-2 was 151%.