Switching between hay and tonka beans depending on the context of the material in a fragrance, coumarin is one of the most widely used and popular aroma chemicals. It was the first synthetic used in a fragrance — 10% of Fougère Royale by Paul Parquet for Houbigant in 1882 (see the formula for this fine fragrance below). A touch of coumarin can naturalise vanillin giving a truer note of vanilla beans, while an overdose contributes a wonderful cut hay scent. This natural coumarin is isolated from cassia bark and may be said to hint at its originating source as it has a slightly warmer, spicier and more pungent odour profile than synthetic coumarin. It lacks that cherry-like note that is part of a synthetic material.