The Japanese mint (Mentha arvensis var. piperascens) belongs to Lamiaceae (the Mint family). It is a perennial herb that is native to all over Japan, as well as the Korean Peninsula and China. This herb grows in wettish places, and it can reach 20-40 cm in height. It spreads by rhizomes. The leaves are oblong with acute serrate edges, and arranged in opposite. The stems, leaves and calyces are covered with pubescences. The pale purple labiate flowers bloom in annular and tiered clusters from August to October. The all parts of plant are scented, and the mentha oil is obtained from the leaves.