Star Anise Drug Interactions, Uses, Safety & More

Star anise is the dried, star-shaped fruit of an evergreen tree called Illicium verum, often known as Chinese star anise. The tree grows mainly in China and Vietnam. Each fruit forms a star with several points, and each point holds a shiny seed.

The spice has a strong, sweet, licorice-like flavor and is a common ingredient in Asian cooking, including five-spice powder and pho broth. People also use it as a tea or supplement in traditional medicine, mostly for stomach and breathing complaints.

One reason star anise is well known is that it is a key natural source of shikimic acid, a compound used by drug companies to help make the antiviral medicine oseltamivir (Tamiflu). Eating star anise does not give you this medicine, though.

People use star anise for many reasons, but solid human research is limited. Most claims come from traditional use, laboratory studies, or animal studies rather than large, well-designed human trials.

• Digestive upset and gas: A traditional use, often as a tea. Evidence in humans is weak.
• Cough and colds: Used traditionally for respiratory complaints, but good clinical proof is lacking.
• Antimicrobial and antifungal: Lab studies suggest compounds in star anise can slow the growth of some bacteria and fungi, but this does not prove it treats infections in people.
• Antioxidant effects: Test-tube studies show antioxidant activity, which has not been shown to translate into clear health benefits.

Overall, star anise is valued as a flavorful spice, but you should not rely on it to treat any medical condition.

Star anise contains aromatic oils, with anethole being a major compound that gives the spice its licorice-like smell and flavor. It also contains shikimic acid, flavonoids, and other plant compounds.

In laboratory research, these compounds appear to have antimicrobial, antifungal, and antioxidant activity. Some researchers believe anethole may relax the digestive tract, which could explain the traditional use for gas and stomach discomfort.

It is important to know that most of this information comes from test-tube and animal studies. These early findings do not prove that star anise works the same way in the human body.

The culinary Chinese star anise (Illicium verum) is generally considered safe when used in normal food amounts. However, there are some important cautions.

Toxic look-alike: Japanese star anise (Illicium anisatum) looks very similar but is poisonous. It contains nerve toxins that can cause vomiting, jumpiness, and seizures. Because the two can be mixed up or contaminate each other, only use products from trusted sources.

Infants: Star anise tea has caused serious reactions, including seizures and irritability, in babies. Do not give star anise tea to infants or young children.

Pregnancy and breastfeeding: Eating star anise as a spice in food is likely fine. But avoid medicinal teas, concentrated extracts, and supplements during pregnancy and breastfeeding, because safety has not been proven and contamination with the toxic species is a real concern.

If you have a known allergy to anise or related plants, use caution. Always talk to your pharmacist or doctor before taking star anise supplements.

In normal food amounts, star anise rarely causes problems for most adults. When side effects happen, they may include allergic reactions such as skin rash or itching, and digestive upset.

More serious effects, including vomiting, restlessness, and seizures, have mainly been linked to contamination with toxic Japanese star anise or to giving star anise tea to infants. These reactions are a reason to be careful with concentrated products and to keep star anise away from babies.

There is no well-established standard medicinal dose for star anise. It is most commonly used as a culinary spice or as a mild tea made from the whole star.

If you use a supplement, capsule, or extract, follow the directions on the product label and do not exceed them. Because product strength varies and quality control matters, choose products from reputable brands.

Talk with your pharmacist or doctor before using star anise for any health purpose, especially if you are pregnant, breastfeeding, or giving it to a child.