Educational information, not medical advice — ask your doctor or midwife.
St John's wort red oil is a skin remedy made from the flowers of Hypericum perforatum. The fresh yellow flowers are steeped in a plant oil, often olive or sunflower. Over a few weeks the oil turns deep red.
In Nordic homes it was dabbed on small burns, sunburn, grazes, bruises and dry skin. The plant is called mäkikuisma in Finland, johannesört in Sweden and prikkperikum in Norway.
Here is the honest verdict. Human evidence for the oil on skin is thin and comes from a few small, weak trials. Long use in folk medicine is not proof that it works, and it is not proof that it is safe.
One point is firm: the oil can make treated skin burn more easily in sunlight.
No one has shown clearly how the red oil helps skin. Most of what we know comes from test tubes and animals.
In lab tests, hyperforin from the plant slows Staphylococcus aureus, a germ often found in wounds. Whether it does the same on a real wound is not known.
In cell studies, the flavonoids appear to damp down inflammation (swelling and redness). In animal wound models, hypericum extracts seem to speed skin closing and raise collagen, the protein that rebuilds skin.
One effect is well established in people. Hypericin makes skin more sensitive to sunlight, so treated skin can burn faster.
The oil base itself also matters. Any plain oil softens skin and holds water in, which eases dryness and tightness.
Red oil is the usual skin form. You may see it sold as Hypericum oil or oleum hyperici. It is a plain infused oil, deep red to red-brown.
It also turns up in salves, creams and ointments. Some are blended with calendula, arnica or beeswax.
Strength varies a lot between products. Home-made oil is not measured at all.
Taken by mouth, St John's wort is sold as tablets, capsules and tea for low mood. Those products are a different matter and clash with many drugs. This page covers the oil used on skin.
The plant has a long record in Nordic and wider European folk medicine. Flowers were picked around Midsummer, near St John's Day in late June, which gave the plant its English name.
Country healers steeped the flowers in oil and used the red result on burns, cuts, bruises and sore backs. The red colour was read as a sign that the plant belonged with blood and wounds.
It was also hung over doors and barns to keep harm away. European writings on the oil go back to the Middle Ages.
The habit carried on into modern Scandinavian home care. This is history, not advice to treat yourself.
Stop the oil and get medical help if any of these happen: - the burn is bigger than your palm, or is on the face, hands, feet or genitals - the burn blisters, looks white or leathery, or feels numb - a wound turns red, hot or swollen, or leaks pus - you get a fever, or red streaks spread from the wound - a cut gapes open or keeps bleeding - the skin is no better after two weeks - you get a strong rash, swelling or burning where the oil went - treated skin burns badly after sun
If you have diabetes or poor circulation, see a nurse or doctor for any wound on your feet.
In the EU and UK, St John's wort skin oil is sold as a cosmetic or a traditional herbal product. In the United States it is sold as a cosmetic or supplement, and is not checked by the FDA 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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