The chief constituent of valerian is a yellowish-green to brownish-yellow oil present in the dried root, varying in content from 0.5 to 2.0%. This variation in quantity may be determined by location; a dry, stony soil yields a root richer in oil than moist, fertile soil. The volatile oils that form the active ingredient are pungent, somewhat reminiscent of well-matured cheese. Though some people remain partial to the earthy scent, some find it unpleasant, comparing the odour to that of unwashed feet.
