Educational information, not medical advice — ask your doctor or midwife.
Santa María, also called altamisa, is the herb known in English as feverfew. Its botanical name is Tanacetum parthenium. It is a small daisy-like plant with yellow-green leaves and a sharp smell.
It is taken mainly to try to prevent migraine headaches. In Latin American homes it has also been used as a tea for fever, period pain and stomach upset.
The honest verdict: human trials point to a small, uncertain benefit for migraine prevention. Results are mixed and most studies are small. Long traditional use is not proof that it works, and it is not proof that it is safe.
Name confusion is common and matters here. In parts of Latin America, altamisa can also mean Artemisia species or ragweed, which are different plants. Check the botanical name on the label.
No one has shown how Santa María works in the human body. The main idea centres on a plant compound called parthenolide.
In test-tube studies, parthenolide appears to block the release of serotonin from platelets, which are tiny blood cells. In the same kind of lab work it seems to damp down inflammation signals.
In cell and animal studies it may also relax the walls of blood vessels. Whether any of this happens in a person's head during a migraine is not established.
There is a wrinkle. Some products hold very little parthenolide, and at least one trial using an extract still showed a small benefit. So other compounds in the leaf may matter too.
The dried leaf is the part used. Capsules and tablets are the most common modern form.
Forms you may meet: - Capsules or tablets of dried leaf, sometimes standardised for parthenolide - A carbon dioxide (CO2) extract, used in the better migraine trials - Tea brewed from the dried leaf, the usual home form in Latin America - Fresh leaves, traditionally chewed - Liquid tinctures made with alcohol - Creams and washes applied to the skin in folk practice
Chewing fresh leaves is the form most tied to mouth ulcers and a swollen tongue. It is also the hardest form to judge for strength.
These forms are not swappable. A home-made tea is not the same product as a CO2 extract tested in a trial.
Feverfew has a long record in European herbal medicine. Writers described it for fever, headache and pains after childbirth. Spanish settlers carried the plant to the Americas.
There it took the names Santa María and altamisa. Home healers used it for headache, cramps, fever and stomach trouble. It was also used to bring on a late period.
Modern interest started in Britain in the 1970s. People with migraine reported relief after chewing leaves daily, and that led to the first trials. These accounts describe past practice, not a plan for treating yourself.
Stop and get urgent help if you have a rash with swelling of the face, lips or tongue, or trouble breathing. That can be a serious allergic reaction.
See a doctor soon if you notice: - Unusual bruising, nosebleeds, or black or bloody stools - Mouth ulcers that do not heal after you stop the herb - A headache that is new, sudden, severe or different from your usual pattern - Headache with fever, a stiff neck, confusion or weakness
Also speak to a doctor if you find you are pregnant while taking it. Stop it and ask for advice.
In the United States it is sold as an ordinary dietary supplement, not an approved drug. In the United Kingdom and Canada, some feverfew products are registered as traditional herbal medicines for migraine prevention, based on long use rather than proof.
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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