Disclosed are a pharmaceutical composition and a health functional food used for prevention and treatment of diabetic peripheral neuropathy, comprising an herb extract of a mixture of Dioscorea Rhizoma and Dioscorea nipponica in a ratio of 3.5:1 (w/w). Having the ability to synergistically increase in vivo levels of nerve growth factor, compared to the extracts from the herbs alone or herb mixtures of other weight ratios, the mixed herb extract is effective for preventing the apoptosis of nerve cells and promoting nerve regeneration. Therefore, the pharmaceutical compositions and the health functional food are preventive and curative for diabetic peripheral neuropathy.