Inhibition effects of peptide hydrolysates from Astragalus membranaceus Bunge. on the expression of the matrix metalloproteinases (MMPs) in human dermal fibroblasts were evaluated in vitro. Crude peptides were obtained by the hydrolysis of proteins extracted from A. membranaceus. Peptides were purified partially by the basis on the molecular weight using 40% polyacrylamide gel electrophoresis before treatment with human dermal fibroblasts. Basis on the doseeffect experiments, expressions of MMPs including MMP-1, MMP-3, MMP-8, MMP-13 in human dermal fibroblasts were evaluated. Expressions of MMP-1, MMP-3, MMP-8 and MMP-13 were reduced in 43%, 5%, 22% and 57% respectively. The mass spectrometric analysis of partially purified peptides from A. membranaceus, which strongly inhibit expressions of MMPs, indicated that the peptides were composed of molecules below 1500 Da.