Educational information, not medical advice — ask your doctor or midwife.
Red maple (Acer rubrum) is a common tree of eastern and central North America. Its inner bark was used as a folk medicine by several Native American nations. It is rarely sold as a herbal product today.
The bark and twigs carry the medicinal record. The leaves are a different story. Wilted or dried red maple leaves are a known poison to horses, and that hazard is well documented.
There are no human trials of red maple for any health purpose. Long traditional use is not proof that a plant works, and it is not proof that it is safe. Treat this page as background, not as a reason to self-treat.
No one has shown that red maple does anything useful in people. What follows is laboratory work and theory.
The bark and leaves are rich in tannins. Tannins are plant compounds that bind protein and taste puckery and dry. In test tubes they tighten tissue and slow the growth of some bacteria.
Lab studies of red maple leaf extract have focused on a compound called ginnalin A. In test tubes it slows enzymes that break starch down into sugar. Whether that changes blood sugar in a person is unknown.
In animals, the picture turns dark. Gallic acid and related compounds from wilted leaves damage red blood cells in horses. Poisoned horses can die, and vets know this pattern well.
No one knows what amount would harm a person, because it has not been studied. That gap is the honest headline here.
There is no standard red maple product on the shelf. That alone is worth knowing before you go looking.
- Inner bark decoction: bark simmered in water. This was the traditional form. - Dried bark or twig pieces: sold now and then by small foraging suppliers.
- Leaf extracts: used in research labs, not sold as consumer products. - Maple sap and syrup: a food, and mostly sugar. Red maple can be tapped, though sugar maple is the usual source.
Because no regulator checks these products, strength and purity vary a lot. Bark sold loose can also be misidentified. Leaves are not a medicinal form in any sense, and should not be eaten.
Red maple bark had a modest but real place in Native American plant medicine. The record comes mainly from ethnobotanists writing in the 1800s and 1900s.
Cherokee practice described a bark wash for sore or inflamed eyes. Bark preparations were also recorded for coughs, cramps, hives and loose bowels. Iroquois and other northeastern nations used related maple barks in similar ways.
Settlers used the bark mostly for ink and dye rather than for healing. Maple sap boiled into syrup was a food and a trade good across the region.
These uses are reported here as history. They were not tested the way a medicine is tested now.
Stop use and see a doctor if anything below appears.
- Dark, red-brown or cola-coloured urine. - Yellowing of the skin or the whites of the eyes. - Unusual tiredness, pale skin or breathlessness. - Eye pain, swelling, discharge or any change in your vision. - A cough lasting more than three weeks, or coughing up blood. - Diarrhoea lasting more than two days, or blood in the stool. - Rash, swelling of the face or lips, or trouble breathing.
If a child or a pet has eaten red maple leaves, call a poison line or a vet straight away.
In the United States, red maple is not an approved drug and is not a common dietary supplement. Maple sap and syrup are ordinary foods. In the UK and EU it is not a licensed or registered herbal medicine, so no authority has checked bark products for safety or quality.
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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