Does Eucalyptus Repel Insects? Science-Backed Facts and How to Use It

If you’re looking for natural ways to keep bugs at bay, you’ve probably wondered whether eucalyptus can help. The short answer is yes—eucalyptus does repel insects, and it’s been used as a natural pest deterrent for generations.

Eucalyptus is an evergreen tree native to Australia that has gained worldwide popularity for its aromatic properties and various health benefits. Beyond its medicinal uses, eucalyptus has proven to be an effective natural insect repellent, making it a popular alternative to synthetic chemical sprays.

This comprehensive guide explores the science behind eucalyptus as an insect repellent, which bugs it works against, how to use it effectively, and important safety considerations.

Why Does Eucalyptus Repel Insects?

Eucalyptus contains several natural compounds that insects find unpleasant or even toxic. The primary active ingredient responsible for its insect-repelling properties is eucalyptol (also called cineole), a naturally occurring organic compound found in eucalyptus oil.

Eucalyptol has a strong, distinctive aroma that interferes with insects’ sensory receptors, making it difficult for them to locate their targets—namely, you. This compound also has mild toxic effects on certain insects, which further enhances its repellent properties.

Other compounds found in eucalyptus oil that contribute to its bug-repelling effects include:

• Limonene
• Alpha-pinene
• Para-cymene
• Citronellal (especially in lemon eucalyptus)

These compounds work synergistically to create an effective barrier against various types of insects.

Which Insects Does Eucalyptus Repel?

Research has shown that eucalyptus can effectively repel multiple types of insects. Here are the most common pests that eucalyptus helps keep away:

Mosquitoes

Eucalyptus is perhaps best known for its mosquito-repelling properties. Lemon eucalyptus oil, in particular, has been recognized by the Centers for Disease Control and Prevention (CDC) as an effective ingredient in insect repellents. Studies have demonstrated that eucalyptus-based repellents can provide protection against mosquito bites for up to 2 hours after application.

Flies

Both house flies and fruit flies are deterred by the strong scent of eucalyptus. The aromatic compounds in eucalyptus oil disrupt their ability to navigate and locate food sources, making eucalyptus an effective natural fly repellent for indoor and outdoor use.

Ticks

Eucalyptus oil has shown promise in repelling ticks, which are vectors for serious diseases like Lyme disease. The oil’s strong odor and chemical composition make it difficult for ticks to detect potential hosts.

Fleas

Pet owners often turn to eucalyptus as a natural flea deterrent. While it shouldn’t replace veterinarian-recommended flea treatments, eucalyptus can be used as a supplementary measure to help keep fleas away from living spaces.

Gnats and Midges

These tiny biting insects are also repelled by eucalyptus. The strong scent acts as a barrier that prevents them from landing on skin or entering indoor spaces.

Moths

Eucalyptus can help protect clothing and stored items from moths. Dried eucalyptus leaves or eucalyptus sachets placed in closets and drawers can deter these fabric-damaging insects.

Ants

While not as commonly discussed, eucalyptus oil can disrupt ant trails and deter these insects from entering homes. The strong scent masks the pheromone trails that ants use to navigate.

Scientific Evidence: Does Research Support Eucalyptus as an Insect Repellent?

Multiple scientific studies have examined the effectiveness of eucalyptus as a natural insect repellent, and the results are promising.

Research has found that a combination of eucalyptus and clove essential oils strongly prevented mosquitoes from landing on skin. The study demonstrated that this natural combination could serve as an alternative to synthetic insect repellents.

Another study examining various plant-based insect repellents found that eucalyptus oil showed significant repellent activity against multiple species of mosquitoes, with protection lasting between 1.5 to 2 hours depending on concentration and formulation.

Lemon eucalyptus oil (derived from the Corymbia citriodora tree, a close relative of eucalyptus) has been particularly well-studied. The CDC recognizes oil of lemon eucalyptus (OLE) as one of the active ingredients in effective insect repellents, placing it alongside more commonly known synthetic options.

Studies comparing lemon eucalyptus oil to DEET (a conventional synthetic repellent) have found that properly formulated lemon eucalyptus products can provide comparable protection against mosquitoes for several hours.

How to Use Eucalyptus as an Insect Repellent

There are several ways to harness eucalyptus’s insect-repelling properties safely and effectively:

Commercial Insect Repellents

The easiest and safest option is to purchase commercial insect repellents that contain eucalyptus oil or lemon eucalyptus oil as an active ingredient. These products have been tested for safety and efficacy and typically provide clear instructions for use.

Look for products that specify the concentration of eucalyptus oil and follow all label directions carefully.

Diluted Eucalyptus Oil Spray

You can create your own eucalyptus insect repellent spray by diluting eucalyptus essential oil with a carrier substance:

• Add 10-15 drops of eucalyptus essential oil to 2 ounces of a carrier oil (such as coconut oil, jojoba oil, or sweet almond oil)
• Alternatively, mix 10-15 drops with 2 ounces of witch hazel or vodka, then add 2 ounces of water
• Pour into a spray bottle and shake well before each use
• Apply to exposed skin, avoiding the face and sensitive areas
• Reapply every 1-2 hours for continued protection

Always perform a patch test on a small area of skin before widespread application to check for allergic reactions or sensitivity.

Eucalyptus Diffusers

Using a diffuser with eucalyptus essential oil can help repel insects from indoor spaces. Add several drops of eucalyptus oil to a diffuser and run it in areas where you want to deter bugs, such as bedrooms, living rooms, or patios.

Fresh or Dried Eucalyptus Leaves

Placing fresh or dried eucalyptus leaves around entry points, windowsills, or outdoor seating areas can help deter insects. You can also hang bundles of eucalyptus leaves in areas where insects tend to congregate.

Eucalyptus Candles

Eucalyptus-scented candles can provide a pleasant aroma while helping to repel insects during outdoor gatherings. The combination of smoke and eucalyptus scent creates an effective barrier against flying insects.

Eucalyptus Sachets

Create sachets filled with dried eucalyptus leaves and place them in closets, drawers, or storage areas to repel moths and other fabric pests.

Important Safety Considerations

While eucalyptus is a natural product, it’s important to use it safely and responsibly. Here are key safety considerations:

Never Ingest Eucalyptus Oil

Eucalyptus essential oil should never be taken internally. Even small amounts can be toxic if consumed, potentially causing serious side effects including nausea, vomiting, diarrhea, dizziness, muscle weakness, difficulty breathing, and in severe cases, seizures or coma.

Consuming as little as 3.5 milliliters of eucalyptus essential oil can lead to serious toxicity.

Dilute Before Topical Application

Pure eucalyptus essential oil is highly concentrated and can cause skin irritation, burning, or allergic reactions if applied directly to skin. Always dilute eucalyptus oil with an appropriate carrier oil or substance before topical use.

The CDC specifically warns against using pure eucalyptus essential oil directly on skin because it hasn’t been adequately tested for safety and efficacy in this form.

Use Caution with Children

Eucalyptus products should be used with extreme caution around children. Children are at higher risk of eucalyptus toxicity, and eucalyptus oil should not be applied to the face or near the nose and mouth of young children.

Oil of lemon eucalyptus products are not recommended for children under 3 years of age. Always consult with a pediatrician before using eucalyptus products on or around children.

Pregnancy and Nursing

There isn’t enough reliable research to determine whether eucalyptus oil is safe for pregnant or nursing women. If you’re pregnant or breastfeeding, consult with your healthcare provider before using eucalyptus products.

Pets

Eucalyptus oil can be toxic to pets, particularly cats and dogs. Never apply eucalyptus oil directly to pets, and use caution when diffusing eucalyptus oil in homes with animals. Ensure pets have access to rooms without eucalyptus diffusion and watch for signs of distress.

Allergic Reactions

Some people may be allergic to eucalyptus. Perform a patch test before widespread use by applying a small amount of diluted eucalyptus oil to the inside of your forearm and waiting 24 hours to check for any reaction.

Medication Interactions

Eucalyptus may interact with certain medications, potentially reducing their effectiveness or causing adverse effects. If you take any medications regularly, consult with a healthcare professional before using eucalyptus products.

Eucalyptus vs. Synthetic Insect Repellents: How Does It Compare?

When comparing eucalyptus to synthetic insect repellents like DEET or picaridin, there are several factors to consider:

Duration of Protection

Synthetic repellents typically provide longer-lasting protection (4-8 hours or more) compared to eucalyptus-based products (1-2 hours). However, properly formulated lemon eucalyptus products can provide protection comparable to lower concentrations of DEET.

Safety Profile

While both natural and synthetic repellents can cause adverse reactions if misused, many people prefer eucalyptus as a more natural alternative with fewer concerns about environmental impact and long-term health effects.

Scent

Eucalyptus has a pleasant, refreshing aroma that many people find appealing, whereas synthetic repellents often have chemical odors that some find unpleasant.

Skin Feel

Eucalyptus-based repellents, especially oil-based formulations, may feel less greasy than some synthetic options, though this varies by product.

Effectiveness

For short-term protection in moderately buggy conditions, eucalyptus products can be quite effective. For extended outdoor activities in areas with high insect populations or disease-carrying mosquitoes, synthetic repellents may offer more reliable protection.

Additional Benefits of Eucalyptus

Beyond its insect-repelling properties, eucalyptus offers several other impressive benefits:

Respiratory Support

Eucalyptus is widely used to help relieve symptoms of respiratory conditions. The eucalyptol compound has anti-inflammatory and mucus-relieving properties that may help with cold symptoms, nasal congestion, sinusitis, and bronchitis.

Antimicrobial Properties

Eucalyptus has natural antimicrobial properties that may help fight bacteria and fungi. This makes it useful in cleaning products and for promoting a hygienic environment.

Pain Relief

Inhaling eucalyptus essential oil may help reduce pain due to its anti-inflammatory and analgesic compounds. Some studies have found that eucalyptus aromatherapy may help relieve pain when used alongside conventional treatments.

Stress Reduction

The aromatic properties of eucalyptus may help promote relaxation and reduce stress. Eucalyptol may decrease activity in the sympathetic nervous system while increasing activity in the parasympathetic nervous system, which promotes relaxation.

Skin Health

Topical application of properly diluted eucalyptus may help improve skin health by increasing ceramide production, which helps maintain the skin’s moisture barrier.

Oral Health

Eucalyptus is commonly used in oral health products due to its antibacterial properties. It may help fight bacteria associated with cavities and gum disease.

Tips for Maximum Effectiveness

To get the best results when using eucalyptus as an insect repellent:

• Reapply regularly: Since eucalyptus-based repellents typically provide 1-2 hours of protection, reapply as needed for continued effectiveness
• Use adequate coverage: Apply repellent to all exposed skin areas, taking care to avoid eyes, mouth, and any wounds or irritated skin
• Combine methods: Use multiple approaches, such as diffusing eucalyptus oil indoors while applying diluted oil to skin when outdoors
• Choose quality products: Use high-quality, pure eucalyptus essential oil or reputable commercial products containing eucalyptus
• Store properly: Keep eucalyptus oil in a cool, dark place to maintain its potency
• Layer protection: In high-risk areas, combine eucalyptus repellent with protective clothing, mosquito netting, and other preventive measures

When to Consider Synthetic Alternatives

While eucalyptus can be an effective natural insect repellent, there are situations where synthetic alternatives may be more appropriate:

• Travel to areas with high risk of mosquito-borne diseases like malaria, dengue fever, or Zika virus
• Extended outdoor activities lasting several hours
• Areas with extremely high insect populations
• When longer-lasting protection is needed and frequent reapplication isn’t practical

Consult with a healthcare provider or travel medicine specialist for recommendations specific to your situation, especially when traveling to areas with disease-carrying insects.

Making Your Own Eucalyptus Insect Repellent

If you’d like to create a custom eucalyptus insect repellent, here’s a detailed recipe:

Basic Eucalyptus Repellent Spray

Ingredients:

• 10-15 drops eucalyptus essential oil
• 10-15 drops lemon eucalyptus essential oil (optional, for enhanced protection)
• 5 drops lavender essential oil (optional, for added scent and mild repellent properties)
• 2 ounces witch hazel or vodka
• 2 ounces distilled water
• 1 teaspoon vegetable glycerin (optional, helps the spray adhere to skin)

Instructions:

1. Combine the witch hazel or vodka with the essential oils in a spray bottle
2. Add the vegetable glycerin if using
3. Add the distilled water
4. Shake vigorously before each use
5. Spray onto exposed skin, avoiding face and sensitive areas
6. Reapply every 1-2 hours or as needed

Store the repellent in a cool, dark place and use within 2-3 months for best results.

Frequently Asked Questions

How long does eucalyptus repel insects?

Eucalyptus-based insect repellents typically provide protection for 1-2 hours after application. The exact duration depends on factors like concentration, formulation, activity level, and environmental conditions such as heat and humidity.

Is eucalyptus safe to use daily?

When properly diluted and used as directed, eucalyptus can generally be used daily on healthy adult skin. However, it’s important to monitor for any signs of irritation or sensitivity, and to give your skin occasional breaks from any topical product.

Can I use eucalyptus oil directly on my skin?

No, pure eucalyptus essential oil should not be applied directly to skin without dilution. It must be mixed with a carrier oil, lotion, or other appropriate diluting substance to prevent skin irritation and adverse reactions.

Does eucalyptus repel bed bugs?

While eucalyptus may have some deterrent effect on bed bugs, it is not considered a reliable treatment for bed bug infestations. Professional pest control is typically necessary to effectively eliminate bed bugs.

Can I use eucalyptus around my garden?

Yes, eucalyptus can be used in garden areas to help repel unwanted insects. However, be cautious about applying it directly to plants, as concentrated eucalyptus oil may harm some vegetation. Planting eucalyptus plants around the perimeter of your garden or using diluted sprays on non-edible surfaces can help deter pests.

The Bottom Line

So, does eucalyptus repel insects? The answer is a definitive yes. Eucalyptus, particularly lemon eucalyptus, has been scientifically proven to effectively repel mosquitoes, flies, ticks, and other common insects for 1-2 hours after application.

The key to success with eucalyptus as an insect repellent lies in proper use: choosing quality products, applying adequate amounts to exposed skin, and reapplying regularly for continued protection. Whether you opt for commercial eucalyptus-based repellents or create your own formulations, this natural alternative can be an effective tool in your pest-prevention arsenal.

However, it’s crucial to use eucalyptus safely. Never ingest eucalyptus oil, always dilute it before topical application, use caution around children and pets, and consult with a healthcare professional if you’re pregnant, nursing, or taking medications.

While eucalyptus offers an appealing natural option for everyday insect protection, consider synthetic alternatives for high-risk situations, such as travel to areas with disease-carrying insects or extended outdoor activities.

Beyond its insect-repelling properties, eucalyptus offers additional benefits including respiratory support, pain relief, stress reduction, and antimicrobial effects, making it a versatile addition to your natural health toolkit.

Whether you’re enjoying a backyard barbecue, hiking through nature, or simply want to keep your home bug-free, eucalyptus provides an effective, pleasant-smelling, and natural way to repel insects.

Sources:

• Centers for Disease Control and Prevention – Mosquito Prevention
• National Center for Biotechnology Information – Essential Oils as Insect Repellents
• National Center for Biotechnology Information – Plant-Based Insect Repellents
• MedlinePlus – Eucalyptus Information
• Environmental Protection Agency – Insect Repellents
• National Center for Biotechnology Information – Eucalyptus Phytochemistry