Guides
How to Use Essential Oils Safely
Tea tree, peppermint, eucalyptus and lavender oil have all been assessed by the EMA. Each has uses where it may help, but all are concentrated substances. The rules below come from the warnings in their EMA monographs.
Updated: October 15, 2026
Rule 1: Do not swallow essential oil as such
Per its monograph, tea tree oil must not be taken by mouth or inhaled. Peppermint oil is taken by mouth only as gastro-resistant capsules (ready-made medicine), and lavender and eucalyptus oil only as dosed ready-made products.
Rule 2: Take special care with young children
Peppermint and eucalyptus oil must not be used in children under 2: menthol and 1,8-cineole can cause reflex breathing arrest and throat spasm. They are also not used in children with a history of seizures.
Tea tree and lavender oil are not recommended under 12.
Rule 3: Dilution and skin
Essential oils are mostly used as diluted preparations. Examples:
- Tea tree oil: products with 0.5–10% oil for larger areas; 1–2 undiluted drops only on small spots
- Peppermint oil (headache): a 10% preparation on the forehead and temples
- Eucalyptus oil: ointment containing 10% oil
- Do not apply to broken or irritated skin; do not touch your eyes with oily hands.
Rule 4: Care with steam and baths
With eucalyptus steam, beware of scalding and keep your eyes out of the steam.
No full essential-oil baths with open wounds, high fever, severe infection, serious circulation problems or heart failure.
Rule 5: Pregnancy and breastfeeding
Safety in pregnancy and breastfeeding has not been established for any of these four oils, and the EMA does not recommend their use.
Frequently asked questions
Can essential oils be swallowed?
No. Tea tree oil must not be taken by mouth. For the others, oral use is only with dosed ready-made products.
Can I use peppermint or eucalyptus oil on a baby?
No. They must not be used under 2 because of the risk of breathing arrest and throat spasm.
How do I dilute an essential oil?
Ready-made diluted products are preferred. Tea tree oil, for example, is used at 0.5–10% on larger areas.
Sources
- European Union herbal monograph on Melaleuca alternifolia (Maiden and Betch) Cheel, M. linariifolia Smith, M. dissitiflora F. Mueller and/or other species of Melaleuca, aetheroleumEMA HMPC · 2015
- European Union herbal monograph on Mentha x piperita L., aetheroleum – Revision 1EMA HMPC · 2020
- Community herbal monograph on Lavandula angustifolia Miller, aetheroleumEMA HMPC · 2012
- European Union herbal monograph on Eucalyptus globulus Labill., Eucalyptus polybractea R.T. Baker, Eucalyptus smithii R.T. Baker, aetheroleum – Revision 1EMA HMPC · 2024
Related herbs
Tea Tree Oil
T Traditional useMelaleuca alternifolia
Tea tree oil is used on the skin only for small wounds, insect bites, small spots and mild athlete's foot itching; it must not be swallowed.
Lavender Oil
T Traditional useLavandula angustifolia
Lavender oil is traditionally used as a bath additive to relieve mild symptoms of stress and exhaustion and to aid sleep.
Peppermint Oil
A Strong clinical evidenceMentha × piperita
Gastro-resistant peppermint oil capsules may ease IBS cramps, wind and pain; oil rubbed on the forehead may ease mild tension headache.
Eucalyptus Oil
T Traditional useEucalyptus globulus
Eucalyptus oil is used as steam or a chest rub for cough with a cold and on the skin for localised muscle pain; never under age 2.