Educational information, not medical advice — ask your doctor or midwife.
What is sea mayweed?
Sea mayweed is a white-and-yellow daisy of northern coasts. It grows on shingle beaches, cliffs, dunes and harbour walls. You find it around the North Atlantic: Iceland, the Faroes, Norway, Britain and Ireland.
Its Icelandic name is baldursbrá, or 'Baldr's brow'. The name comes from Norse myth. The plant looks much like chamomile, but it has almost no smell, which is why it is also called scentless mayweed.
Here is the honest verdict. No human trials have tested sea mayweed for any health use. Traditional use is real, but it is not proof that the plant works, and it is not proof that it is safe.
Why do people think it does anything?
Mostly because it looks like chamomile. The two plants sit in the same family, the daisy family. People in coastal Scandinavia treated sea mayweed as a stand-in for it.
There is no proven mechanism in people. Lab work on daisy-family flavonoids, such as apigenin and luteolin, shows some calming of inflammation in cell studies. Whether a cup of tea delivers enough of them to do anything in a person is unknown.
One difference matters. German chamomile holds a rich blue oil that carries much of its studied activity. Sea mayweed has very little scented oil, so it is not a like-for-like swap.
How is it sold or used?
Sea mayweed is not a mainstream supplement. You will not find it in most pharmacies. It reaches people in a few simple ways.
- Dried flower heads, brewed as a weak tea. - Fresh flowering tops, used in home-made washes or poultices. - Dried flowers from the odd craft or forager sale.
A tincture (an alcohol extract) shows up rarely, from small herbal makers.
There is no standard extract and no standard strength. One batch can differ a lot from the next. Wild stands near roads, farms or harbours may also carry spray residue or pollution.
What did tradition use it for?
The records are thin. Sea mayweed appears more often as a named plant of folklore than as a listed remedy. The Icelandic name baldursbrá ties it to Baldr, a god in Norse myth.
In Iceland, the Faroes and coastal Norway it was treated as a near twin of chamomile. Some people brewed a weak flower tea. Some used a cooled brew as a wash for sore or itchy skin.
Folk writers also mention it for mild stomach upset and for settling people before sleep. These notes are short and often second-hand. They describe habit, not results.
Stop using it and see a doctor if you get a rash, hives, swollen eyelids or wheezing. Also see a doctor if stomach upset or itching keeps going after you stop.
Call emergency services now if your lips, tongue or throat swell. Do the same for trouble breathing, a tight chest, or feeling faint. These are signs of a severe allergic reaction.
Do not use it in place of care for a problem that is getting worse.
Sea mayweed is not approved as a medicine in the UK, the US or the EU. It is not a controlled plant, and it is sold only rarely, mostly as dried flowers.
Picking wild plants is limited in some places. Nature reserves and protected coastal sites often forbid it, so check local rules first.
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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