The aim of this study was to explore the potent phosphodiesterase type 5 (PDE %) inhibitor from various herbal medicines for erectile dysfunctions. In this study, 61 herbal medicines, which were extracted with ethanol, have been investigated with PDE 5 assay using enzyme inhibitory activity on 22 species of herbal medicines. Of these, 5 species of herbal medicines, Cnidium monieri, Cuscuta chinensis, Epimedium koreanum, Morinda officinalis, and Tribulus terrestris were exhibited stronger inhibitory effect against phosphodiesterase 5 (PDE 5) among 61 species; Cnidium monieri ($IC_{50}=33.7{mu}g/ml$), Cuscuta chinensis ($IC_{50}=65.7{mu}g/ml$), Epimedium koreanum ($IC_{50}=90.3{mu}g/ml$), Morinda officinalis ($IC_{50}=48.7{mu}g/ml$) and Tribulus terrestris ($IC_{50}=32.5{mu}g/ml$).