Educational information, not medical advice — ask your doctor or midwife.
Mouse-ear hawkweed is a small yellow-flowered plant of dry grassland across Europe. French herbals call it piloselle. The dried leaves and flowering tops are made into tea, tincture or capsules.
It was used in European folk practice mainly as a diuretic (water pill), to make you pass more urine. People also took it for coughs and for mild puffiness in the legs. Some old recipes used it on cuts and grazes.
Here is the honest verdict. There are almost no human trials of this plant. Nearly everything claimed for it comes from folk use, lab dishes or animal tests.
Long traditional use is not proof that a remedy works. It is also not proof that it is safe. Keep that in mind for every claim on this page.
No one has shown in people how mouse-ear hawkweed acts in the body. The ideas below come from lab and animal work only.
In animal studies, extracts of the plant raised urine output. That fits the folk use as a water pill. The same effect has not been measured properly in humans.
The plant contains umbelliferone, a coumarin. In test tubes, umbelliferone slows the growth of some bacteria, including Brucella. Whether it reaches useful levels in your body after a cup of tea is unknown.
In cell studies, the flavonoids in the plant appear to mop up reactive molecules and damp down signs of inflammation. These are dish findings. They do not tell you what a tea will do for a cough or a swollen ankle.
You will mostly meet it as a dried herb for tea. Other forms are sold too.
- Loose dried leaf and flower, brewed as an infusion. - Tea bags, often blended with birch leaf, dandelion or horsetail. - Liquid tincture or fluid extract in alcohol.
- Capsules or tablets of powdered herb or dry extract. - Dried herb sold as part of French "drainage" blends.
Single-herb products are less common than mixtures. With a blend, the other herbs may carry their own risks and interactions. Read the full ingredient list before you buy.
Mouse-ear hawkweed has a long record in European folk medicine. It was written up in French, German and British herbals from the sixteenth century onward.
Healers mainly treated it as a water pill. It was given for fluid in the legs, for gravel and stones, and to "flush" the urinary tract.
It also had a second life as a cough herb. Old texts used it for whooping cough and bronchitis, often sweetened with honey.
The crushed fresh plant was laid on wounds. In the 1940s researchers took interest in its umbelliferone content after lab tests against Brucella bacteria. That work never led to an approved medicine.
Stop using it and see a doctor if any of these happen.
- You get a rash, itching, wheezing, or swelling of the lips, tongue or face. Swelling or wheezing needs emergency care. - You feel faint, very thirsty, weak or your heart races. - You pass much less urine than usual. - You see blood in your urine. - You get fever, back pain or burning when passing urine. - Your swelling gets worse, or spreads, or affects only one leg. - A cough lasts more than three weeks, or you cough up blood.
Also tell your doctor you are taking it before any planned surgery.
In the EU and UK it is sold as a food supplement and herbal tea. It is not a licensed medicine and has no approved health claim. In the US it is sold as a dietary supplement, which means it is not reviewed for effect before sale.
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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