Present report deals with the plant form and the essential oil components of Mentha japonica Makino derived from Terauchi in Fukushima prefecture, which grow experimentally in three different conditions of standard with Hyponex compost, shade with Hyponex compost and fine sands with non-compost. The essential oils of M. japonica grown in standard, shade and fine sands harvested blooming time consisted mainly of limonene (0.3, 0.2, 0.9%), 3-octyl acetate (0.1, 0.1, 0.2%), 3-octanol (1.9, 1.7, 1.0%), menthone (19.3, 19.7, 8.0%), isomenthone (1.1, 1.1, 0.6%), neomenthyl acetate (0.0, 0.0, 0.1%), linalool (0.2, 0.2, 0.3%), menthyl acetate (3.0, 3.9, 16.0%), neoisopulegol (0.2, 0.3, 0.8%), isomenthyl acetate (0.3, 0.2, 0.3%), neomenthol (1.8, 1.5, 1.9%), terpinen-4-ol (0.2, 0.3, 0.3%), neoisomenthol (0.5, 0.6, 0.8%), isoisopulegol (0.2, 0.2, 0.3%), menthol (30.6, 24.8, 33.9%), pulegone (31.2, 37.3, 25.5%), isomenthol (0.1, 0.2, 0.1%), α-terpineol (0.2, 0.5, 0.2%), piperitone (1.0, 0.6, 0.3%) and piperitenone (0.1, 0.1, 0.1%), respectively. Biosynthetic proceed to pulegone, menthone, menthol and its acetate in the essential oils of the stunted type were faster than those of standard and long stem types. “Hai-himehakka,” M. japonica Makino form. prostrata Sugimoto is equivalent to the long stem type appeared by variations of M. japonica adapted to growing environment, so that it is not forma
