Educational information, not medical advice — ask your doctor or midwife.
Blood wiss is a climbing vine from the Caribbean. Botanists call it Cissus verticillata, once listed as Cissus sicyoides. It belongs to the grape family.
It goes by many island names. In Jamaica it is snake withe. In Cuba it is bejuco ubí, and in Haiti liane molle.
The stems, leaves and sap are the parts used. Home healers boiled them into a tea for high blood pressure (hypertension) and for "cooling the blood". The same tea was given for sugar trouble and for heat in the skin.
Here is the honest verdict. Human evidence for any of these uses is very thin. Long use in a tradition shows the plant is familiar, but it does not prove the plant is safe or that it works.
No one has shown how blood wiss works in the human body, or that it works at all.
In rats and mice, leaf extracts have lowered blood sugar. Some animal work also reports a mild drop in blood pressure. Whether a cup of home-brewed tea does this in a person is not known.
In test tubes and cell studies, the plant shows antioxidant activity. That means it can mop up reactive molecules in a dish. A dish is not a body, and this result does not predict a health effect.
The cut vine gives a slippery sap, rich in a plant gum called mucilage. Tradition read that slick feel as proof the plant "cools" hot blood. That is folk reasoning about how the plant feels, not a measured effect.
Some animal reports suggest a weak water pill (diuretic) action, meaning more urine. If true in people, it could shift salts and fluid. This matters most for the drug interactions listed further down.
Blood wiss is mainly a home remedy, not a shelf product.
The usual form is fresh or dried stem and leaf, boiled into a tea. Healers also use sap from the freshly cut vine.
Crushed leaves are used on the skin as a poultice. Some island traditions use a warm leaf wash for swelling or rash.
Outside the Caribbean you may find dried cut vine in botánicas and market stalls. Capsules and tinctures are uncommon.
Be careful with labels that only say "Cissus". Most such products are Cissus quadrangularis, a different plant with a different use. The two are not interchangeable.
Nothing on sale is standardised. Two bags of the same vine can differ a lot in strength.
Blood wiss has a long standing in Caribbean home medicine. Island healers passed the plant down through families rather than through books.
In Jamaica, where it is called snake withe, the boiled vine was taken for pressure. In Cuba, bejuco ubí was given for sugar and for swelling. In Haiti, liane molle appeared in cooling baths and washes.
"Cooling the blood" was a core idea in these traditions. Heat in the blood was blamed for rashes, boils and a racing feeling. Slippery, watery plants like this one were chosen to cool that heat.
The vine also had practical uses. The tough stems were twisted into cord, and the sap was used as a soap substitute.
This history tells you what people did. It does not tell you what the plant does, and it is not a reason to treat a diagnosed illness yourself.
Stop using it and call your doctor if you feel dizzy, faint or oddly weak.
Also call if you notice shaking, sweating, hunger or confusion, which can mean low blood sugar (hypoglycaemia). Check your sugar if you have a meter.
Get urgent care, the same day, for any of these:
- Swelling of the lips, tongue or throat, or trouble breathing. - Fainting, or a blood pressure reading far below your usual. - A blood sugar reading that will not come back up. - Yellow eyes or skin, dark urine, or pain under the right ribs. - A skin sore that spreads, turns hot, or leaks pus.
See your doctor before starting if you are being treated for blood pressure, diabetes, kidney or liver disease.
In the United States it may be sold as a dietary supplement or a plain dried herb. The FDA does not approve it as a medicine and does not check health claims made for it.
In the UK and the EU it is not an approved herbal medicine. It is traded as a plant product, and quality is not policed.
Across the Caribbean it is an everyday bush remedy, gathered and sold without licence.
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.
One email with the summary. We'll also send a short weekly evidence update — unsubscribe any time.
