Educational information, not medical advice — ask your doctor or midwife.
Tormentil is a small wild plant with yellow flowers that grows across Europe. Herb users take the dried root, which is very rich in tannins (plant chemicals that pull tissue tight and make the mouth feel dry). Its Latin name is Potentilla erecta.
It is used most often for short bouts of diarrhoea (loose, watery stools). It is also used as a mouth rinse or gargle for a sore mouth, sore gums or sore throat.
This page covers the single herb on its own, not blends or mixed products. The human evidence is thin: one small trial in children, plus a long record of folk use. Long use in tradition is not proof that a herb works.
Tormentil root is packed with tannins, and that is the best guess for how it acts. Tannins bind to protein in the lining of your gut and mouth. This may tighten the surface and make it weep less, which could slow diarrhoea and soothe a raw throat.
Lab tests also hint that tormentil extracts slow the growth of some germs and calm swelling. Those tests were done in dishes and in animals, not in people. How much of that happens in a human gut is unknown.
This is a plausible idea, not a proven one. No study has shown, step by step, what the root does inside the body.
Tormentil comes as dried chopped root for making a tea (more exactly a decoction, where you simmer the root rather than steep it). It also comes as a tincture, which is the root soaked in alcohol.
You may also see it as a powder in capsules, as a ready-made liquid extract, and in mouthwashes or throat sprays. Strengths vary a lot between products, so follow the label on the pack you have.
Tormentil grows on heaths, moors and poor grassland across Europe. Herbal books from the Middle Ages onward list the root for loose bowels and for bleeding gums.
It stayed a common country remedy in Britain, Ireland, Germany and Scandinavia. The root was also used to tan leather and to dye it red. German herbal guidance still lists it for mild diarrhoea and for a sore mouth or throat.
See a doctor if diarrhoea lasts more than two days in an adult, or more than one day in a child under five or in an older person.
Get medical help the same day if you see blood in the stools, black tarry stools, a fever above 39C, or severe belly pain.
Get help urgently if you notice signs of dehydration (your body drying out): a very dry mouth, dizziness when you stand, passing little or no urine, sunken eyes, or a child who is floppy and hard to wake. Also stop and get advice if you get a rash, swelling of the lips or face, or trouble breathing after taking it.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
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