Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate. The effectiveness ratings for EUCALYPTUS are as follows:

Insufficient evidence to rate effectiveness for…

  • Asthma. Early research shows that eucalyptol, a chemical found in eucalyptus oil, might be able to break up mucous in people with asthma. Some people with severe asthma have been able to lower their dosage of steroid medications if they take eucalyptol. But don’t try this without your healthcare provider’s advice and monitoring.
  • Bronchitis. Some research shows that taking a specific combination product containing eucalyptol, a chemical found in the oil, and extracts of pine and lime by mouth for at least 2 weeks improves symptoms and reduces flare-ups in people with bronchitis.
  • Dental plaque. Early research shows that chewing gum containing 0.3% to 0.6% extract can reduce dental plaque in some people.
  • Gingivitis. Early research shows that chewing gum containing 0.4% to 0.6% eucalyptus extract can improve gingivitis in some people.
  • Bad breath. Early research shows that chewing gum containing 0.4% to 0.6% extract can improve bad breath in some people.
  • Head lice. Early research shows that applying eucalyptus oil and lemon tea tree oil might help to get rid of head lice, But it does not seem to be as effective as applying tea tree oil and lavender oil or benzyl alcohol, mineral oil, and triethanolamine.
  • Headache. Early research shows that applying a combination product containing eucalyptus oil, peppermint oil, and ethanol to the head does not reduce pain in people with headaches. However, the product might help people with headaches relax and think better.
  • Acne.
  • Bladder diseases.
  • Bleeding gums.
  • Burns.
  • Diabetes.
  • Fever.
  • Flu.
  • Liver and gallbladder problems.
  • Loss of appetite.
  • Ulcers.
  • Stuffy nose.
  • Wounds.
  • Other conditions.

More evidence is needed to rate the effectiveness for these uses.

Side Effects Of Eucalyptus

Eucalyptus leaf is LIKELY SAFE when consumed in the small amounts found in foods. There isn’t enough information to know if supplements that contain larger amounts of leaf are safe when taken by mouth.

Eucalyptol, a chemical that is found in the oil, is POSSIBLY SAFE when taken by mouth for up to 12 weeks.

Eucalyptus oil is POSSIBLY UNSAFE when applied directly to the skin without being diluted. It can cause serious problems with the nervous system. There is not enough information to know if it is safe to apply diluted eucalyptus oil to the skin.

Eucalyptus oil is LIKELY UNSAFE when it is taken by mouth without first being diluted. Taking 3.5 mL of undiluted oil can be fatal. Signs of poisoning might include stomach pain and burning, dizziness, muscle weakness, small eye pupils, feelings of suffocation, and some others. Eucalyptus oil can also cause nausea, vomiting, and diarrhea.

Warnings & Precautions

  • Pregnancy and breast-feeding: Eucalyptus is LIKELY SAFE for pregnant and breast-feeding women when consumed in food amounts. But don’t use the oil. Not enough is known about safety during pregnancy or breast-feeding.
  • Children: Eucalyptus oil is LIKELY UNSAFE for children when taken by mouth, applied to the skin or inhaled. While some research shows that diluted eucalyptus oil may be safe to use as a shampoo to treat lice, there are reports of seizures and other nervous system side effects in infants and children exposed to eucalyptus oil. Infants and children should not use eucalyptus oil due to the serious potential side effects. Not much is known about the safety of using eucalyptus leaves in children. It’s best to avoid use in amounts larger than food amounts.
  • Cross-allergenicity: Eucalyptus oil and tea tree oil contain many of the same compounds. People who are allergic to eucalyptus oil might also be allergic to tea tree oil or other essential oils.
  • Diabetes: Early research suggests eucalyptus leaf might lower blood sugar. There is concern that using eucalyptus while taking medications for diabetes might lower blood sugar too much. Blood sugar levels should be monitored closely.
  • Surgery: Since eucalyptus might affect blood sugar levels, there is concern that it might make blood sugar control difficult during and after surgery. Stop using eucalyptus at least 2 weeks before a scheduled surgery.

Eucalyptus Dosage

The appropriate dose of eucalyptus depends on several factors such as the user’s age, health, and several other conditions. At this time there is not enough scientific information to determine an appropriate range of doses for eucalyptus. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult your pharmacist or physician or other healthcare professional before using.


Consult your doctor or pharmacist.


All information has been provided courtesy of MedLinePlus from the National Library of Medicine and from the FDA.