Educational information, not medical advice — ask your doctor or midwife.
Guácimo is the bark, leaf and fruit of Guazuma ulmifolia, a tree of tropical America. It is also sold as bay cedar, caulote or West Indian elm. The inner bark is the part most often made into a tea.
The bark is rich in tannins and a slippery gum called mucilage. In Latin American home medicine it was taken mostly for diarrhoea. The sweet fruit is eaten and blended into cold drinks.
Here is the honest verdict on evidence. Human trials are almost absent, so its effects in people stay unproven. Long traditional use means the plant is familiar, not that it works or that it is safe.
No one has shown how guácimo acts in the human body. Almost all of the work is in test tubes and rodents.
In animal studies, bark extracts slowed gut movement and relaxed gut muscle. That is the usual explanation offered for the old use in diarrhoea. Whether it does this in people is not established.
In test tubes, the tannins bind proteins and pull tissue tight. This may explain the dry, puckering taste of the tea. Tannins also bind bacteria and toxins in a dish, which is not the same as helping a sick gut.
In rats and mice, bark extracts lowered blood sugar and relaxed blood vessels. These are animal findings only. They are the main reason to be careful if you take diabetes or blood pressure drugs.
You will most often meet guácimo as dried bark, sold loose or in chips.
Common forms include:
- Loose dried bark for a simmered tea (decoction) - Tea bags, often blended with other herbs - Powder and capsules - Liquid extracts and tinctures - The fresh or dried fruit, used in sweet drinks - Bark washes and rinses used on skin and hair
Strength is not standardised. Two products with the same label weight can differ a lot. Products sold loose in markets are rarely tested for purity.
Guácimo has a long record across Mexico, Central America and northern South America. Healers used the bark tea mainly for diarrhoea and dysentery.
Other recorded folk uses were for fever, cough, skin sores and hair washing. Some communities used it for kidney and urinary complaints. These uses were handed down by custom, not tested.
The tree had everyday jobs too. Farmers fed the leaves and fruit to cattle. Sugar makers used the slimy bark to help clear cane juice.
Stop and see a doctor if any of these happen.
- Diarrhoea lasting more than two days, or any blood in the stool - Fever with the diarrhoea - Signs of drying out: little urine, sunken eyes, dizziness, no tears - Shaking, sweating or confusion, which can mean low blood sugar (hypoglycaemia) - Yellow skin or eyes, or dark urine - Rash, swollen lips or trouble breathing; this needs emergency care
Tell your doctor you have been taking guácimo. Bring the package if you can.
In the United States guácimo is sold as a dietary supplement, not as an approved medicine. In Mexico and Central America the bark and fruit are sold openly in markets as a herbal remedy and food. No drug regulator has approved it to treat any illness.
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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