Objectives This study was aimed to evaluate the effects of Daeyoungjeon (hereinafter referred to DYJ) treatment on the injury of articular cartilage induced by monosodium iodoacetate in rats. Methods Twenty-four male rats were divided into normal, osteoarthritic control and DYJ group. Rats of normal group were injected with 0.1 ml physiological saline, rats of control and DYJ groups were injected with 0.1 ml monosodium iodoacetate (3 mg/ml) into each left and right knee joint cavities. Rats of DYJ group were administrated extracts of DYJ during 60 days per orally. At 60 days after treatment, gross lesions, area and proteoglycan contents of articular cartilage, histopathological lesions, immunohistochemistry on matrix metalloproteinases (MMP-2, MMP-3, MMP-7) were evaluated. Results Grossly, degenerative changes of articular cartilages were observed weak in DYJ group. The areas of articular cartilages were broader significantly in DYJ group. The proteoglycan contents in articular cartilages were lesser significantly in DYJ group. Histopathologically, the chondrocyte score was lesser significantly in DYJ group. MMP-3 expression in articular cartilages was observed weak in DYJ group. Conclusions From above results, DYJ treatment has inhibitory effects on the injuries of articular cartilage induced by monosodium iodoacetate in rats, and it`s effects may be related with down regulation of MMP-3. (J Korean Med Rehabil 2017;27(2):9-17)