Steam-distilled from the leaves of Gaultheria, wintergreen has an unmistakable sharp, sweet, medicinal smell — the smell of an old-fashioned muscle rub, and of American root beer.
It is also, by a wide margin, the most hazardous essential oil we sell, and we are going to spend this page saying so rather than describing how nice it is.
What it actually is
Wintergreen oil is roughly 96 to 99 per cent methyl salicylate. Not "contains"; is. Methyl salicylate is a salicylate — the same chemical family as aspirin — and the body handles it the same way.
The consequence is a number worth knowing: a single teaspoon of wintergreen oil is roughly equivalent to about 7 grams of aspirin — more than twenty adult tablets, and a potentially fatal dose for a small child. Deaths of children who drank wintergreen oil are documented in the medical literature. This is not a cautious formula of words. It is the reason this bottle needs to live somewhere a child cannot reach, ever.
Do not use it at all if
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You are buying it for a child. Wintergreen is not for children, in any dilution, by any route.
- You are pregnant or breastfeeding.
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You are allergic or sensitive to aspirin or any salicylate, including anyone with aspirin-exacerbated respiratory disease (asthma with nasal polyps).
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You take an anticoagulant or antiplatelet — warfarin, a DOAC, aspirin, clopidogrel. Methyl salicylate is absorbed through the skin and can add to their effect. There are published case reports of serious bleeding from topical methyl salicylate in people on warfarin.
- You have a bleeding disorder, kidney disease, or surgery coming up.
- You are giving it to a pet. Salicylate poisoning in cats and dogs is well documented.
If you do use it — the rules that actually matter
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Never neat, never internally, never on broken skin. Keep it to a low dilution — well under three per cent in a carrier oil — and to small areas.
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Never under a bandage, wrap, cling film or heat. Occlusion and warmth multiply how much passes through the skin, and this is the mechanism behind most reported cases of harm. No hot baths, no heat pads, no using it before a sauna, no covering the area.
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Never over large areas of the body, and not repeatedly through the day. Salicylate accumulates.
- Not on the face, and nowhere near eyes or mucous membranes.
- Stop immediately and seek advice if you get ringing in the ears, nausea, rapid breathing, dizziness or confusion — those are the early signs of salicylate toxicity.
An honest note about how this oil is usually sold
Wintergreen is almost always marketed for aching muscles and joints. We are not going to make that claim: relieving pain is a medicinal claim, which a cosmetic or aromatic product may not make under EU law, and no health claim is authorised for any essential oil.
What is worth understanding is why the claim exists. Methyl salicylate genuinely is a licensed medicinal ingredient — it is the active in a number of pharmacy rubefacient creams. But those are regulated medicines at a controlled, tested concentration, with a leaflet, a maximum dose and a pharmacist. A 10 ml bottle of near-pure methyl salicylate is not that, and treating it as an interchangeable version of one is precisely how people get hurt.
If you want relief from a sore muscle, a pharmacy product is the safer and better-tested route. We would genuinely rather tell you that.
Storage and emergencies
Cool, dark, tightly closed, child-resistant cap on, stored out of sight and reach of children — higher than you think, and not in a bathroom cabinet a child can climb to.
If anyone swallows this, or a child gets hold of the bottle, treat it as an emergency. In Portugal call CIAV on 800 250 250 — free, 24 hours a day — or 112. Take the bottle with you.