Amphibians have a large variety of antimicrobial peptides that serve as natural innate barriers limiting microbial infection or, in some instances, act as an integral component in response to inflammation or microbial infection. A novel peptide with antibacterial effects and without hemolytic activity was purified from skin secretions of Rana ridibunda by multisteps cation-exchange FPLC, reversed-phase HPLC and was called Ridibundin 1. Circular dichroism spectra revealed that this peptide strongly prefers to form an amphipathic ?-helical structure in the presence of 50% trifluoroethanol. Acting as wide-spectrum microbicides against a variety of bacteria, Ridibundin 1 also shows no hemolytic activity on erythrocyte. These properties reveal its unique characteristics and potential therapeutic application