Oil of spearmint is a yellowish to yellowish green liquid with a sweet, slightly cool aroma of spearmint leaves. The relative density was 0.92~0.97, and the specific rotation was -45°~-60°. The main ingredients are carvone (about 60%), menthol, isomenthol, pentonone, dihydrocarvone, limonene, hydrocarvene, pinene, folium olefin, dihydrocarvinol, 3-octanol, octanol acetate, etc.