To search for the aldose reductase (AR) inhibitors from Korean folk plants, the inhibition of rat lens AR in vitro using the methanol (MeOH) extracts from Korean folk plants was investigated. Among fifty four Korean folk plants tested, the MeOH extract of Cedrela sinensis showed highest inhibition of AR ($IC_{50}$ value, 2.52 ${mu}g/ml$). The plant C. sinensis has a possibility of new natural resources for the development of AR inhibitor for the prevention of diabetic complications.