Educational information, not medical advice — ask your doctor or midwife.
Tea-leaved willow is a small northern shrub willow. Its bark holds salicin, an aspirin-like compound. Nordic folk practice used willow bark for aches, sore joints and fever.
The plant grows in Iceland, Norway, Sweden, Finland and parts of northern Britain. Icelandic speakers call it gulvíðir. It is usually a low, bushy shrub rather than a tree.
Here is the honest verdict. No good human trials have tested this species. Long folk use is not proof that it works, and it is not proof that it is safe.
What we do have are trials of other willow barks, mostly white willow and purple willow. Those point to modest, short-term help for back pain. Whether tea-leaved willow matches them is unknown.
The main lead is salicin, the aspirin-like compound in willow bark. Your body turns salicin into salicylic acid. That step is well described in people.
Salicylic acid damps down prostaglandins, body chemicals that drive pain, swelling and fever. This is the same broad route that aspirin-type drugs use.
Willow bark is weaker and slower than aspirin at the amounts sold. It also seems to thin the blood less.
Even so, the risk pattern is the aspirin family of risks. That includes peptic ulcer (a sore in the stomach lining).
Two things are not settled. Nobody has measured how much salicin tea-leaved willow delivers in practice. Salicin levels swing with the species, the season and the individual plant.
Lab work also suggests that flavonoids and tannins in willow bark add to the effect. That has not been shown to matter in people.
Tea-leaved willow is rarely sold under its own name. Most willow products on shelves use white willow or purple willow bark.
Common forms include:
- Dried bark, simmered as a decoction (a strong boiled tea).
- Tinctures, which are alcohol extracts.
- Capsules and tablets of dried extract, often labelled with a salicin amount.
- Leaf or twig infusions, mainly a folk practice rather than a commercial product.
Foraged bark is the least predictable form. You cannot know its strength, and willow species are easy to confuse.
Willow bark has a long record in European medicine. Greek and Roman writers noted it for pain and fever. Nordic folk practice later used local willow barks the same way.
In Iceland, gulvíðir was a familiar shrub with everyday uses. Willow wood and shoots served for fuel, basketry and winter fodder. Bark was also used in tanning hides.
The scientific thread runs through willow too. Salicin was isolated from willow bark in the 1820s. Chemists later built on it to make aspirin, which reached the market in 1899.
Written records tend to speak of willow bark in general. Few name tea-leaved willow on its own.
Stop and get urgent medical help if you notice any of these:
- Black, tarry stools, or blood in your vomit. - Swelling of the lips, face or tongue, or trouble breathing. - A spreading rash or hives. - Severe stomach pain.
Stop and book a normal doctor's appointment if you get ringing in the ears, ongoing nausea, easy bruising, or pain that has not settled in two weeks. Tell your doctor you have been taking willow bark.
In the UK and the EU, willow bark is sold as a herbal supplement. Some white willow bark products hold a traditional herbal registration for backache and minor joint pain. In the United States it is sold as a dietary supplement and is not approved as a drug. Tea-leaved willow itself is not a registered medicinal product anywhere.
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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