1. High in antioxidants
Although you cannot eat fresh, whole eucalyptus leaves, dried leaves can be made into tea.
Be careful not to mistake this tea for eucalyptus oil, which can be toxic if consumed. Choose a tea that’s labeled “eucalyptus leaves tea,” and don’t add eucalyptus essential oil to your tea.
Eucalyptus leaves are a great source of antioxidants, particularly flavonoids, which protect your body from oxidative stress and free radical damage.
The main flavonoids in eucalyptus include catechins, isorhamnetin, luteolin, kaempferol, phloretin, and quercetin. Diets rich in these compounds may protect against certain cancers, heart disease, and dementia (1Trusted Source, 2Trusted Source).
For example, a large study including 38,180 men and 60,289 women found that a diet high in flavonoids was associated with an 18% lower risk of fatal heart disease (3Trusted Source).
Eucalyptus tea is a good source of these antioxidants and generally recognized as safe for adults. However, children are at high risk of eucalyptus toxicity and should get approval from a healthcare professional before drinking this tea (4).
Summary Eucalyptus tea is high in flavonoids, which are antioxidants that may lower your risk of certain cancers, heart disease, and dementia.
2. May relieve cold symptoms
Eucalyptus is widely used as a natural cold remedy and is a common ingredient in cold and cough products.
Research has shown that it can decrease mucus and expand the bronchi and bronchioles of your lungs. It’s also a natural anti-inflammatory agent (5Trusted Source, 6Trusted Source).
The main ingredient responsible for these properties is eucalyptol, also known as cineole, which is a compound found in eucalyptus oil (5Trusted Source, 6Trusted Source, 7).
Some research has shown that eucalyptol relieves cold symptoms like cough frequency, nasal congestion, and headache by decreasing inflammation and mucus buildup (5Trusted Source, 6Trusted Source).
Furthermore, eucalyptol may help improve asthma symptoms.
One 12-week study gave 32 people with bronchial asthma either 600 mg of eucalyptol or a placebo per day. Those in the eucalyptol group required 36% less medication to control their asthma symptoms, compared with those in the control group, who needed 7% less (8Trusted Source).
Eucalyptus oil can be inhaled through your nose and may provide some cold symptom relief. It’s also found in many topical decongestants. However, because even small doses of the oil can be toxic, you should avoid consuming it (9Trusted Source).
Be sure to consult your healthcare provider before using eucalyptol or changing your medications.
Summary Eucalyptus contains a compound called eucalyptol, which has been found to decrease nasal congestion, cough frequency, and cold-related headaches. It may also improve asthma symptoms, although more research is needed.
3. May treat dry skin
Using eucalyptus may improve dry skin by increasing its ceramide content.
Ceramides are a type of fatty acid in your skin that’s responsible for maintaining its barrier and retaining its moisture. Those who experience dry skin, dandruff, or skin disorders like dermatitis and psoriasis usually have lower ceramide levels (10Trusted Source).
Topical eucalyptus leaf extract has been found to boost skin ceramide production, water-holding capacity, and skin barrier protection. It contains a compound called macrocarpal A, which appears to stimulate ceramide production (10Trusted Source).
In a study in 34 people, using a scalp lotion containing eucalyptus leaf extract and synthetic ceramide significantly decreased scalp redness, itchiness, dryness, and scaliness (11Trusted Source).
Hence, many hair and skin products contain eucalyptus leaf extract.
Summary Eucalyptus leaf extract has been shown to increase ceramide production in the skin, which may improve dry skin and dandruff. More research is needed to confirm this.
4. May reduce pain
Inhaling eucalyptus essential oil may decrease pain.
Eucalyptus contains many anti-inflammatory compounds, such as cineole and limonene, which may act as pain relievers (12Trusted Source).
A 3-day study in 52 people who had undergone knee replacement surgery found that inhaling eucalyptus oil dissolved in almond oil for 30 minutes daily significantly decreased perceived pain and blood pressure levels, compared with inhaling pure almond oil (12Trusted Source).
However, another study in 123 people with cancer found no improvements in perceived pain after inhaling eucalyptus oil for 3 minutes prior to a medical procedure, suggesting that more research is needed (13Trusted Source).
Summary Inhaling eucalyptus oil may help reduce pain levels. However, more research is needed.
5. May promote relaxation
Eucalyptus is widely believed to decrease symptoms of stress.
In one study, 62 healthy people experienced significant reductions in pre-surgery anxiety after inhaling eucalyptus oil. Eucalyptus contains eucalyptol, which has been found to possess anti-anxiety properties (14Trusted Source).
Furthermore, inhaling eucalyptus oil for 30 minutes has been associated with lower blood pressure in patients after knee surgery, which suggests that it has a calming effect (12Trusted Source).
Researchers believe that it decreases the activity of your sympathetic nervous system — your stress response system — and increases the activity of your parasympathetic nervous system, which promotes relaxation (12Trusted Source).
Summary Eucalyptus oil is associated with decreased blood pressure and anxiety. It’s believed to activate the parasympathetic nervous system, which promotes relaxation.
6. Can help keep your teeth healthy
Eucalyptus leaf extract, known as eucalyptol, may improve dental health.
Eucalyptus leaves contain high amounts of ethanol and macrocarpal C — a type of polyphenol. These compounds are associated with lower levels of bacteria that can cause cavities and gum disease (15Trusted Source).
A study in 97 people found those who chewed gum with eucalyptus leaf extract 5 times per day for at least 5 minutes had a significant decrease in plaque buildup, gum bleeding, and gum inflammation, while the control group experienced no improvements (15Trusted Source).
For this reason, eucalyptol is commonly added to mouthwash.
Summary Chewing gum with eucalyptus leaf extract has been found to significantly decrease plaque buildup on teeth and signs of gum disease. It’s added to many types of mouthwash and other oral health products.
7. Can act as a natural insect repellent
Eucalyptus oil is a natural insect repellent, mainly due to its eucalyptol content.
Research has shown that it’s effective at warding off mosquitoes and other biting insects for up to eight hours after topical application. The higher the eucalyptol content of eucalyptus oil, the longer and more effectively it works as a repellent (16).
In fact, the Center for Disease Control and Prevention lists lemon eucalyptus oil — derived from the lemon eucalyptus tree — as an approved and powerful insect repellant (17).
Additionally, eucalyptus oil may treat head lice. In one randomized study, this oil was twice as effective as a popular head lice treatment at curing head lice. However, a recent review suggests that more research is needed (18Trusted Source, 19Trusted Source).
Summary Eucalyptus oil contains a compound called eucalyptol, which has been shown to repel mosquitoes and other biting insects. It may also be an effective treatment for head lice, but more research is needed.