Anise oil is an essential oil extracted from the small fruits (commonly called seeds) of the anise plant, Pimpinella anisum. It has a distinctive sweet, licorice-like flavor and aroma, driven primarily by a compound called trans-anethole, which makes up 85 to 90% of the oil. You’ll find it in everything from liqueurs and baked goods to cough remedies and toothpaste.
How Anise Oil Is Made
The anise plant is an herbaceous annual in the Apiaceae family (the same family as carrots, celery, and fennel), originally from Asia, Egypt, and Greece. The oil comes mainly from the plant’s small, ridged fruits, though the roots can also be used. Anise seeds yield up to 3% essential oil by weight, which is relatively modest compared to some other aromatic plants.
The traditional extraction method is steam distillation: steam passes through the crushed seeds, carries the volatile aromatic compounds with it, and the oil is separated from the condensed water. Newer methods use pressurized carbon dioxide instead of steam, which keeps temperatures lower and better preserves heat-sensitive compounds. Both methods produce a pale yellow oil with that unmistakable licorice scent.
What’s in It
Trans-anethole dominates the chemical profile, typically making up 85 to 90% of the oil. This single compound is responsible for most of the flavor, fragrance, and biological activity. The remaining fraction includes smaller amounts of other aromatic compounds like gamma-himachalene, but trans-anethole is so dominant that it essentially defines what anise oil smells, tastes, and does.
Anise Oil vs. Star Anise Oil
These two oils taste remarkably similar but come from completely unrelated plants. True anise oil comes from Pimpinella anisum, a small annual herb. Star anise oil comes from Illicium verum, an evergreen tree in a different plant family entirely. The confusion is understandable: both oils are rich in trans-anethole (93 to 96% in both cases), which is why they share that licorice flavor.
The practical differences matter if you’re buying oil. Star anise yields significantly more essential oil per harvest, around 4.3 to 6.7% compared to anise’s roughly 1.7%. This makes star anise oil more widely available commercially. If a product label just says “anise oil” without specifying the species, it may contain star anise oil instead. Check for the Latin name if the distinction matters to you.
Common Uses
Anise oil works as a flavoring agent across a wide range of products. It’s the signature flavor in several traditional liqueurs, including ouzo, sambuca, arak, and absinthe. In baking, it shows up in cookies, cakes, and breads, particularly in Mediterranean, Middle Eastern, and South Asian cuisines. Food manufacturers also use it as a natural preservative and coloring agent.
Outside the kitchen, anise oil appears in oral hygiene products like toothpaste and mouthwash, where it contributes both flavor and mild antimicrobial properties. It’s also used in cough drops, digestive remedies, and aromatherapy blends. The U.S. Food and Drug Administration classifies anise oil as Generally Recognized as Safe (GRAS) for use as a flavoring agent in food.
How It Works in the Body
Anise oil’s most well-studied effect is as an antispasmodic, meaning it helps relax smooth muscle tissue. In the digestive tract, this relaxation is what gives anise its reputation as a carminative, something that eases gas, bloating, and stomach cramps. The mechanism involves triggering a signaling pathway in smooth muscle cells that tells them to relax rather than contract.
The same muscle-relaxing effect extends to the airways. Research on animal tissue shows that anise compounds can relax the smooth muscle lining the trachea by blocking certain receptors that trigger constriction. This is why anise has been used in traditional medicine as an expectorant and cough remedy for centuries, and why you still find it in some over-the-counter respiratory products.
Estrogenic Activity
Trans-anethole, the main compound in anise oil, has demonstrated estrogenic activity in laboratory assays, meaning it can mimic the hormone estrogen to some degree. This is relevant for anyone with hormone-sensitive conditions, including certain types of breast cancer, endometriosis, or uterine fibroids. The estrogenic effect is mild compared to actual estrogen, but it’s consistent enough across studies that the concern is real rather than theoretical.
Safety Considerations
The anise seeds you sprinkle on bread or stir into tea are safe in normal culinary amounts. The essential oil is a different story. It’s vastly more concentrated than dried seeds or extract, and a small volume contains a large dose of trans-anethole. In large or even moderate amounts, this compound can be neurotoxic and may interact with medications.
For topical use, recommended dilution ratios range from 0.5 to 2% for adults. In practical terms, that’s about 1 to 2 drops of essential oil per tablespoon of a carrier oil like jojoba or sweet almond oil. Undiluted application can irritate the skin.
Internal use of the concentrated essential oil is generally discouraged without professional guidance. Inhaling the aroma through a diffuser is considered a safer way to get mild digestive or calming benefits without the risks of ingestion.
Anise oil should be avoided during pregnancy and breastfeeding. Essential oil components are small, fat-soluble molecules that can cross the placenta into fetal circulation and pass into breast milk. The fetal central nervous system is particularly vulnerable because it’s still developing. Combined with anise oil’s estrogenic properties and the lack of established safe dosage thresholds for pregnant women, avoidance is the straightforward recommendation.