Eucalyptus (Eucalyptus spp.) is a native tree of Australia and Tasmania, widely recognized for the oil extracted from its leaves. This essential oil is used in various food products, pharmaceuticals, and cosmetics. Thanks to its natural properties, eucalyptus oil is valued for its potential effects on respiratory symptoms, inflammation, and oral health.

While commonly found in cough drops and lozenges, scientific evidence supporting its benefits in humans is still limited.

Potential Health Benefits of Eucalyptus

High in Antioxidants

Eucalyptus oil contains antioxidant compounds that help protect cells from oxidative damage. In the food industry, these antioxidants are used to preserve freshness and extend shelf life. In the human body, they may reduce cellular damage and inflammation by neutralizing free radicals.

May Ease Respiratory Issues

Eucalyptus has a long history of use in managing cold and flu symptoms like cough and congestion. Although clinical data is limited, some research suggests eucalyptus oil may help reduce cough frequency.

One study focused on eucalyptol (1,8-cineole), the main component of eucalyptus oil. Participants with bronchitis who took 200 mg of eucalyptol three times daily experienced less frequent coughing than those who did not.

Could Help With Pain Relief

Inhaling eucalyptus oil may reduce pain, especially in inflammatory conditions like rheumatoid arthritis. In one study, patients inhaled eucalyptus oil three times daily over a month and reported lower pain levels during the final two weeks of treatment.

Might Have Antiviral Properties

Laboratory and animal studies suggest that eucalyptus compounds may inhibit viruses like influenza, herpes simplex, and even SARS-CoV-2 by preventing viral entry and replication. However, no human studies have confirmed these antiviral effects.

Supports Oral Health

Eucalyptus oil may help reduce dental plaque and gum inflammation. A small study tested a toothpaste containing eucalyptus and Salvadora persica (miswak). It found both toothpastes reduced plaque, and the one with eucalyptus also decreased gum bleeding in patients with gingivitis.

Eucalyptus as a Supplement

Eucalyptus is available in several supplement forms, such as capsules, oils, and liquid extracts. Some respiratory relief supplements also include eucalyptus.

While a few studies have tested eucalyptol doses of 600 mg per day (typically split into three 200 mg doses), there is not enough research to establish a safe or effective standard. Some users report side effects like nausea, nosebleeds, and headaches. Always consult your healthcare provider before using eucalyptus supplements.

Choosing Safe Supplements

Look for third-party testing certifications from organizations like U.S. Pharmacopeia to verify quality and ingredient accuracy.

Possible Risks of Eucalyptus

Although eucalyptus oil is generally recognized as safe (GRAS) for food use in very small amounts, consuming large doses can be dangerous. Accidental ingestion of just 4–5 mL of eucalyptus oil in adults and as little as 1.9 g in children has led to fatal outcomes.

Topical use of undiluted eucalyptus oil is also not recommended due to the risk of neurotoxicity. Even diluted oil may pose risks, and its safety profile remains uncertain.

Drug Interactions

Eucalyptus oil can interfere with several medications, including:

  • Diabetes drugs

  • Amphetamines

  • Medicines metabolized by the liver

If you take prescription medications or have chronic conditions, consult your doctor before using eucalyptus in any form.

Other Common Uses of Eucalyptus

Beyond medicinal purposes, eucalyptus is used in:

  • Skincare and haircare: Included in gels, creams, and ointments for its soothing and aromatic properties
  • Insect repellents: Thanks to eucalyptol, eucalyptus oil is sometimes used as a natural bug repellent
  • Air fresheners and aromatherapy: Used in diffusers and sprays, though safety concerns remain with long-term inhalation exposure

A Quick Recap

Eucalyptus is a versatile plant used in everything from throat lozenges to skincare products. It may offer relief from respiratory symptoms, reduce inflammation, and support oral hygiene. However, high doses can be harmful, and more human research is needed to confirm its full benefits and safety.

Always speak with a healthcare professional before using eucalyptus supplements, especially if you're on medications or have underlying health concerns.