Generally speaking, a plant produces essential oil from only one part of the plant such as fruit or flower, root or leaf, seed or bark. With the bitter orange tree (Citrus aurantium var. amara) we get three different and distinct oils, a rarity in aromatherapy.
Steam distillation of this plant produces neroli from the blossoms and petitgrain from the leaves and twigs. With cold pressing of the rinds of the fruit, we get bitter orange essential oil.
The most known and revered oil from this tree is neroli. Although it is from the bitter orange, the aroma is a sweeter floral. This oil is useful for relieving anxiety or insomnia and for healing dry or sensitive skin (Lavabre). Distillation gives an orange flower floral water that is used in baking.
Petitgrain is used in skincare and for the nervous system like neroli, but it is more woodsy smelling and costs less. Both are used in colognes with petitgrain being a cheaper replacement. It also helps with dyspepsia and gas, so it may have a place after a Thanksgiving feast (Lawless).
The last is bitter orange, with a scent like both sweet orange and grapefruit. The uses for this oil are similar to sweet orange: anti-inflammatory, antiseptic, sedative, and for digestive upset and fungal infection (Lawless). Because the fruit is sour and bitter it is rarely eaten, however it is used as a flavoring agent in the liqueurs Triple Sec, Grand Marnier, and Cointreau.
All three oils can be combined with lavender for an anti-anxiety blend.
Lavabre M. (1990). Aromatherapy Workbook. Rochester, VT: Healing Arts Press.
Lawless J. (1995). The Illustrated Encyclopedia of Essential Oils. Rockport, MA: Element Books, Inc.