Amphibians secrete small antimicrobial polypeptides from their skin that have been explored as alternatives to conventional antibiotics.In this study,mass spectrometry was used to identify and characterize protein secretions from the skin of a Chinese frog,Rana dybowskii.The skin of this kind of frog has been used in traditional Chinese medicine for centuries as a remedy against inflammation.Functional studies showed the peptide Dybowskin-2CDYa has potent antimicrobial activity both against Gram-positive and Gram-negative bacteria and has extremely low haemolytic activity to human red blood cells.Taken together,these studies suggest that this novel peptide can be further developed as an antimicrobial agent.