Educational information, not medical advice — ask your doctor or midwife.
Grey alder is a small northern tree, Alnus incana. In Norway and Sweden it is called gråor. In Finland it is harmaaleppä.
The part used in folk remedies is the bark, and sometimes the young leaves. Boiled in water, it makes a dark, bitter, drying brew. Nordic households used that brew as a mouth rinse, a gargle and a skin wash.
Here is the honest verdict. There are no human trials on grey alder for any health use. Long standing in tradition is not proof that it works, and it is not proof that it is safe.
No one has shown how grey alder works in people, because it has not been tested in people.
The bark is rich in tannins. In test tubes, tannins bind to proteins and make surface tissue feel tight and dry. That drying effect is the likely reason it was used as a gargle and a wash.
The bark also holds compounds called diarylheptanoids. The best known is oregonin. In cell studies and in animals, oregonin appears to lower some markers of inflammation.
Whether that happens in a person who sips a bark tea is unknown. The amounts used in a lab dish are not the amounts that reach your blood.
In laboratory tests, alder bark extracts slow the growth of some bacteria and fungi. These tests use strong extracts on a plate, not on human skin. No study has shown that effect on a real wound.
Grey alder is a folk material, not a mainstream supplement. Most shops do not stock it at all.
Dried bark, chopped for boiling, is the traditional form. The strained liquid was used warm as a gargle or wash.
A few small herbal makers sell alder bark tincture, which is an alcohol extract. Dried leaf is sold less often.
Alder wood is widely sold as smoking chips for fish and meat, and as timber and firewood. Those are not medicinal products and should not be treated as one.
Grey alder held a steady place in Nordic country medicine. Finnish, Swedish and Norwegian households kept dried bark on hand.
Healers boiled the bark and used the liquid as a rinse for sore gums and sore throats. The same brew was used to wash cuts, grazes and itchy rashes.
The bark was also a dye and a tanning material. Fishermen soaked nets in alder brew to toughen the fibres.
Records of drinking it are thinner, and several mention stomach upset. Folk texts mostly describe it as something used on the outside, not as a daily drink.
Stop using it and get emergency help now if your lips, tongue or throat swell, if you wheeze, or if you struggle to breathe. Those are signs of a severe allergic reaction.
Stop and see a doctor the same week if any of these happen:
Your sore throat lasts more than a week, or comes with fever, rash or trouble swallowing.
A wound you washed turns redder, hotter or starts to leak pus, or red streaks spread from it.
You get ongoing stomach pain, repeated vomiting, or black or bloody stools.
Loose stools last more than two days, contain blood, or come with fever.
A rash spreads after you put the wash on your skin.
Tell your doctor or pharmacist that you have been using grey alder, including how you prepared it.
Grey alder is not an approved herbal medicine in the Nordic countries or the wider EU, and it has no European herbal monograph. It is sold as a craft and dye material, and as wood chips for smoking food.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
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