Educational information, not medical advice — ask your doctor or midwife.
Sweet clover (Melilotus officinalis) is a tall yellow-flowered legume used in European folk medicine. The dried flowering tops and leaves are the parts used. It is also called melilot or meliloto.
The plant smells of fresh-cut hay. That smell comes from coumarin, its main compound. Coumarin is also the reason this herb needs care.
The short evidence verdict: human proof for the whole herb is weak. Long folk use is not proof that it works, and it is not proof that it is safe.
The traditional idea is that sweet clover helps fluid drain out of swollen legs. In animal and lab work, coumarin appears to help the body clear protein-rich fluid from puffy tissue. Whether this happens in people taking the herb is not settled.
In lab tests, flavonoids in the plant act as antioxidants. That does not tell you what the tea does in a human body.
One point matters more than any of this. Well-dried sweet clover is not a blood thinner. If the cut plant goes mouldy, fungi turn its coumarin into dicoumarol.
Dicoumarol is a true blood thinner. It caused fatal bleeding in cattle fed spoiled sweet clover hay. That finding led to the drug warfarin.
So the hazard is not the fresh herb alone. It is damp, musty or mouldy plant material, and it is real.
Sweet clover is sold in a few plain forms: - Dried cut herb for tea - Tinctures (alcohol extracts) in drops - Dry extracts in capsules or tablets, often standardised to coumarin - Creams, gels and ointments for bruises and tired legs - Compresses made from the dried herb
In parts of Europe, isolated coumarin was sold as a drug for swelling. Some of those products were pulled or restricted after reports of liver injury.
Quality matters more here than with most herbs. Buy from a seller who tests the material. Never use herb that smells musty or looks damp or discoloured.
European folk healers used melilot for centuries for swelling, bruises and sore joints. The dried herb was laid on as a warm poultice or plaster.
Medieval and early modern apothecaries stocked melilot plasters. Herbals of the time also listed it as a mild calming tea and an eyewash.
In the twentieth century, German health authorities listed the herb for leg vein problems and for bruises. That listing rested on tradition and limited data, not on strong trials.
Its best-known mark on medicine is indirect. Spoiled sweet clover hay killed cattle in the 1920s, and work on that outbreak produced warfarin.
Stop taking it and call a doctor the same day if you notice: - Yellow skin or yellow eyes - Dark urine or pale stools - Pain under the ribs on your right side - Ongoing nausea, no appetite or unusual tiredness
Get emergency care now if you have: - Bleeding that will not stop, or a heavy nosebleed - Blood in your urine, or black tarry stools - Vomit that looks like coffee grounds - Large bruises with no cause
Also see a doctor if one leg becomes swollen, red, hot or painful. That can be a clot and needs urgent checking, not an herb.
In the European Union, sweet clover is sold as a traditional herbal product and as tea, and coumarin levels in food are capped by law. Some oral coumarin medicines were restricted or withdrawn in Europe after reports of liver injury. In the United States it is sold as a dietary supplement and is not approved as a drug.
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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