Educational information, not medical advice — ask your doctor or midwife.
Jackass bitters is a bitter-tasting leaf used as a bush tea in the Caribbean. The plant is Neurolaena lobata, a shrub in the daisy family. The leaves are the part people use.
It grows wild across the Caribbean, Central America and northern South America. In Haiti and Dominica it is known as zèb-a-pik. In Trinidad and Tobago many people call it bitter bush.
Folk healers reached for it for fever, worms, sugar in the blood, and sores on the skin. Long use in a tradition is not proof that a remedy works, and it is not proof that it is safe. Both things have to be shown in people, and for this plant they have not been.
Here is the short verdict. The lab and animal work is interesting. Good human studies are almost absent, so no health claim for this plant is settled.
Almost everything known about how this plant acts comes from test tubes and animals. None of it has been confirmed in people.
In test-tube work, extracts slow Plasmodium falciparum, the parasite behind most malaria. Extracts have also slowed Leishmania, another parasite, in lab dishes. Whether a cup of tea does anything like this inside the body is unknown.
In cell studies, the plant's bitter compounds appear to damp down signals that drive swelling and pain. In rodents, some extracts lowered blood sugar and reduced swelling. Rodent results often fail to repeat in humans.
Lab tests also show the extracts can kill bacteria, fungi and some cancer cells in a dish. A substance that kills cells in a dish is not a treatment. It can just as easily mean the substance is hard on your own cells.
There is no accepted explanation for how jackass bitters would work in a person, because no one has shown that it does.
The common form is a tea made from fresh or dried leaves. This is how it is used in most Caribbean homes.
Other forms you may meet:
- Tinctures, where the leaf sits in alcohol. - Leaves steeped in rum as a household bush tonic. - Capsules of dried leaf powder, sold online.
You may also find:
- Washes and poultices put on the skin. - Mixed bush-medicine blends sold in markets, often with several other plants.
Labels rarely state how much active material is in the product. Blends may not list every plant they contain.
Jackass bitters has long standing as a Caribbean bush medicine. It was used on many islands and on the Central American mainland.
Healers gave the leaf tea for fever and for illness thought to be malaria. It was also given for worms and other gut parasites, and for "sugar" in the blood. Crushed leaves were laid on sores, cuts and ringworm.
Maya healers in Belize and Guatemala used the same plant for similar complaints. Written records of its use go back to the colonial period, and field surveys from the 1900s onward list it again and again.
In some places it was also used to bring on a late period. That history is one reason the plant is kept away from pregnancy today.
Stop and see a doctor if you get:
- Yellow skin or eyes, dark urine, or pale stools. These can mean liver trouble. - Severe belly pain, or vomiting that will not stop. - A rash, swollen lips or face, or trouble breathing. Get emergency help for these. - Shaking, sweating, confusion or faintness, which can mean low blood sugar. - A fever that is not better in 24 to 48 hours, or that comes with chills and sweats.
Also see a doctor before you start if you take any daily prescription medicine.
Jackass bitters is not approved as a medicine in the United States, the United Kingdom or the European Union. Where it is sold there, it is a herbal supplement, so no agency checks that it works or that the dose is safe. Across the Caribbean it is sold freely in markets as a traditional bush medicine, with no strength standard.
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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