Wintergreen and Sweet Birch: Oils with the Scent of a Warming Ointment That Belong Under Lock and Key

In short: Wintergreen and sweet birch are 93–99 % methyl salicylate, a substance related to aspirin. They smell like mint sweets, but they are the riskiest oils in a home medicine cabinet: a teaspoon drunk by a child can kill. On the skin adults only, 1 % at most, briefly and on a small area. Not for children, in pregnancy, in aspirin allergy and while taking warfarin.

You know the scent of wintergreen even if you have never heard of it: it is in warming back ointments, in some chewing gums and in American "root beer". The scent is due to methyl salicylate. The plant stores it in the leaves (wintergreen) or in the bark (sweet birch) in an inactive form, and it is released during distillation. The result is two oils that are chemically almost identical.

That is why we write about them in one article. Pěstík sells both, BIO wintergreen and BIO sweet birch. Both have their place in massage blends for adults, but with rules that are stricter than for any other oil in our range. Please read them in full before you open the bottle.

Why Methyl Salicylate Is So Dangerous

In the body methyl salicylate turns into salicylic acid, just like aspirin. The difference is in the concentration. A medical review by Davis (Journal of Emergency Medicine, 2007) states that wintergreen oil contains 98 % methyl salicylate and that in children under 6 years several well-documented deaths were associated with swallowing a teaspoon (5 ml) or less. The American Association of Poison Control Centers in its guideline from 2007 writes:

• in a child under 6 years, anything more than a lick or a taste is a reason for transport to the emergency department,
• in children from 6 years and adults, more than 4 ml may cause poisoning,
• vomiting should not be induced.

What to do if a child tastes or drinks the oil: do not induce vomiting, take the bottle with you and call the emergency service 155 or the Toxicological Information Centre (224 919 293, 224 915 402, 24 hours). Symptoms of salicylate poisoning (vomiting, rapid breathing, ringing in the ears, confusion) may begin only after several hours, so do not wait for them to appear.

Wintergreen or Sweet Birch?

A study by Dosoky et al. (Plants, 2022) analysed 27 commercial samples of "sweet birch oil" and in none found substances typical of true birch. Instead it found traces of wintergreen, synthetic methyl salicylate or castor oil. Genuine birch oil is rare and expensive, and the market is therefore full of substitutes. For safety this changes nothing, the rules below apply to both oils and to synthetic methyl salicylate.

Beware also of confusion with our silver birch. It has no methyl salicylate and we write about growing it in the article birch in the garden.

Who Must Not Use Wintergreen and Sweet Birch

• Children: not at all, neither on the skin nor in a diffuser in their room. Store the bottle locked, just like medicines. The Tisserand Institute points out that even two-year-olds can unscrew a cap and drink the contents.
• Pregnancy and breastfeeding: do not use.
• Allergy or sensitivity to aspirin and salicylates, including asthma that worsens after aspirin.
• Warfarin and other blood-thinning medicines, clotting disorders, planned surgery. A case report by Joss and LeBlond (2000) describes a woman whose INR rose to 12.2 after eight days of rubbing her knees with a gel containing methyl salicylate. Methyl salicylate is absorbed through the skin.
• Concurrent use of other products with methyl salicylate, for example warming ointments and gels for muscles. The doses add up.
• Cats: salicylates are very dangerous for cats. Do not use the oil in a household where a cat could get at the blend, and never apply it to animals. More in the article essential oils and pets.

If You Are an Adult and None of This Applies to You

Three Blends for Adults

• Fresh study (diffuser): 1 drop of wintergreen, 2 drops of orange, 1 drop of peppermint.
• Forest scent (diffuser): 1 drop of sweet birch, 2 drops of Himalayan cedar, 1 drop of lemon.
• Calves after a run (10 ml of jojoba, 1.5 % in total): 1 drop of wintergreen, 1 drop of lavender, 1 drop of rosemary. Apply to the calves, no more than twice a day and for at most 3 days in a row.

A massage blend without salicylates that you can use long-term can be put together from rosemary, lavender and juniper. You will find inspiration in the article therapeutic massages with essential oils.

Traditional Use

The leaves of wintergreen were used by the indigenous peoples of North America for tea and compresses, and since the 19th century oil of wintergreen and sweet birch has been added to ointments for aching muscles and joints. Methyl salicylate is still the active ingredient of some over-the-counter warming products, in a precisely given amount. A home blend from an essential oil does not replace such a product and should not even try to. The oil is never swallowed.

Storage

• A locked cabinet, just like medicines. Not on a shelf in the bathroom.
• Close the dropper after use, do not leave the bottle on the table or in a handbag.
• Label a mixed massage blend clearly ("external use only, dangerous for children").
• Cool and dark, the oil lasts several years, methyl salicylate is relatively stable.

The general safety rules are summarised in the article safe use of essential oils, the rules for children in the article essential oils and children.

Frequently Asked Questions

Is wintergreen poisonous?

If swallowed, yes. The oil is about 98 % methyl salicylate and in small children several deaths were associated with drinking a teaspoon or less. On the skin at low dilution it is usable in adults, but only short-term.

What is the difference between wintergreen and sweet birch?

Chemically almost none, both oils are 93–99 % methyl salicylate. Wintergreen is distilled from the leaves of the shrub Gaultheria, sweet birch from the bark of the tree Betula lenta. The safety rules are the same.

Can I use wintergreen if I take warfarin?

No. Methyl salicylate is absorbed through the skin and may strengthen the effect of warfarin; a case of a dangerous rise in INR after an ordinary knee gel has been described.

What should I do if a child drinks wintergreen oil?

Do not induce vomiting, take the bottle and call 155 or the Toxicological Information Centre 224 919 293. Symptoms may come only after several hours, do not wait for them.

How many drops of wintergreen for a massage?

Adults only and 1 % at most, that is 2 drops per 10 ml of carrier oil, on a small area and for no longer than a few days. Not in the bath and not under heat.

Is wintergreen suitable for dogs and cats?

No. Salicylates are especially very dangerous for cats. Never use the oil or blends on animals and store them out of their reach.

Recommended Products

• BIO Wintergreen, essential oil 10 ml – wintergreen leaves from India; adults only, max. 1 %, store locked.
• BIO Sweet birch, essential oil 10 ml – Betula lenta bark from Canada, the same use and the same rules as wintergreen.
• BIO Lavender, essential oil 10 ml – for a massage blend, where it replaces part of the wintergreen.
• BIO Rosemary, essential oil 10 ml – muscle massage without salicylates (not in epilepsy).
• BIO Jojoba 10 ml – a carrier oil for low dilution.

Sources

• Davis J. E.: Are one or two dangerous? Methyl salicylate exposure in toddlers, Journal of Emergency Medicine 2007 – PubMed 17239735
• Chyka P. A. et al. (American Association of Poison Control Centers): Salicylate poisoning: an evidence-based consensus guideline for out-of-hospital management, Clinical Toxicology 2007 – PubMed 17364628
• Joss J. D., LeBlond R. F.: Potentiation of warfarin anticoagulation associated with topical methyl salicylate, Annals of Pharmacotherapy 2000 – PubMed 10860133
• Dosoky N. S. et al.: Authentication and Market Survey of Sweet Birch (Betula lenta L.) Essential Oil, Plants 2022 – PMC9412571
• Tisserand Institute: Safety Guidelines – tisserandinstitute.org
• General University Hospital in Prague: Toxicological Information Centre – vfn.cz

Updated: 27 September 2026