(R) -Citronellol (D-Citronellol) is an alcoholic monoterpene found in geranium essential oil. (R) -Citronellol inhibits degranulation of mast cells and does not affect caffeine bitterness perception. (R) -Citronellol can be used in decorative cosmetics, toiletries as well as in non-cosmetic products[1][2][3].