Aniseed essential oil comes from the seeds of the anise plant, which has the botanical name Pimpinella anisum. (Note that this is not the same plant as star anise.) The seeds themselves have a long history of use in both food and medicines, and the oil can also be used in food and medicine, as well as having some interesting additional uses.

Culinarily, the oil is sometimes used to flavor sweets, like black licorice, cakes or cookies, or in alcoholic liqueurs. It is also used as a flavoring in things like toothpaste and mouthwash, and it can be used in perfumes.

Therapeutically, aniseed oil is thought to have a wide variety of uses. For instance, it's thought to generally boost the circulatory, respiratory and digestive systems. It's been used to treat headaches, muscle pain, flatulence, cramps, bronchitis, rheumatism, colic, hangovers, menstrual pain, nausea, vertigo and indigestion, among other things. It is also considered antiseptic, laxative, expectorant, diuretic, antispasmodic, carminative, and stimulant, and has been used to kill insects and parasites. It is also thought to reduce nervousness, anxiety and emotional discomfort related to fear or introversion.

How aniseed oil is used to treat the above conditions varies, but methods of use include inhaling the scent, putting the oil in a bath, adding the oil to an ointment, and blending the oil with carrier oils to be used in massage. Aniseed is not recommended for those with skin conditions or for pregnant women, and it is thought that the use of too much aniseed can decrease circulation.

Additionally, aniseed oil is applied to fishing lures to attract fish, and used by hunters as a scent cover and to attract deer and bears. It was also reportedly put into bearings during the building of British steam locomotives so that its smell could provide warning of overheating.