Perfume is a complex mix of oils and chemicals, but the specific formula for any perfume is usually a closely-guarded secret. It takes many years for the fragrance industry to develop and refine its processes for extracting fragrant compounds from natural flowers, fruits, woods, herbs, and seeds. Then the odorants must be blended and diluted for use in perfume.
The smell of a perfume changes throughout the day, depending on how your skin interacts with it and how long you wear it. This is because perfumes contain top notes, middle notes and base notes. The top notes are usually a bright and cheerful blend of citrus, floral and herb scents, which last only minutes on the skin, but they will mellow with time as the perfume interacts with your unique body chemistry.
Many modern perfumes also include synthesized odorants, which can provide the desired fragrance at a lower cost than naturally occurring compounds. For example, coumarin, linalool and other natural aromatics found in orchids are often synthetically reproduced to imitate the same effect on the nose.
The most important ingredient in any perfume is the perfume oil, which contains the essential fragrance of a particular flower or plant. Early civilizations used various extraction methods to obtain such oils, including boiling, enfleurage, distillation and maceration. The most popular method today is steam distillation.