Educational information, not medical advice — ask your doctor or midwife.
Guayaba is the guava tree, Psidium guajava. The fruit is eaten as a food across the Americas and Asia. The leaves are brewed as a tea in Latin American home care.
Two very different things share the name. The fruit is a sweet food that is high in vitamin C and fibre. The leaf is used as a herb, mainly for diarrhoea and stomach cramps.
The honest verdict on the leaf: evidence in people is thin. A few small trials hint at help for sudden diarrhoea, period pain and the blood sugar rise after a meal. None of this is settled.
Guayaba leaf has a long and respected place in Latin American home care. Long use is not proof that it works, and it is not proof that it is safe. Those are separate questions, and this page keeps them apart.
Most of what we know about how guayaba leaf might work comes from the lab, not from people.
In test-tube studies, leaf tannins and flavonoids slow the growth of some gut bacteria. Whether that happens inside your gut is not established.
In animal studies, quercetin from the leaf relaxes gut muscle and slows gut movement. That may explain the easing of cramps seen in one small human trial.
In cell and animal work, leaf extracts block alpha-glucosidase, an enzyme that breaks starch down into sugar. Slower breakdown could blunt the blood sugar rise after a meal. Small, short human studies point the same way.
The fruit works in a simpler way. It is a strong food source of vitamin C. Vitamin C prevents and treats scurvy, and that effect is proven in people.
Guayaba is sold both as a food and as a herb.
Food forms include fresh fruit, juice, nectar, jam and the firm paste sold as ate or bocadillo. These are eaten for taste and for vitamin C.
Herb forms are made from the leaf. Dried leaf is sold loose or in tea bags. Capsules, tablets and liquid tinctures of leaf extract are also sold.
In Mexico, a standardised guava leaf product is registered as a herbal medicine for diarrhoea. Some mouthwashes and toothpastes list leaf extract.
At home, cooled leaf tea is sometimes used as a mouth rinse or a skin wash. Strength varies widely between brands and between home brews.
Guayaba leaf has been used for centuries in Mexico, Central America, the Caribbean and northern South America.
Healers brewed the leaves for loose stools, griping belly pain and wind. Cooled tea was used as a gargle for sore gums and as a wash for sores.
Spanish and later writers recorded the plant moving with trade to Asia and Africa. Similar leaf uses took hold there, which says the plant was valued, not that it was tested.
The fruit was never seen as a medicine. It was simply food, and a valued one.
Stop and see a doctor if any of these happen.
Diarrhoea lasting more than two days in an adult, or more than 24 hours in a child. Blood or black colour in the stool. Fever above 38.5C (101.3F).
Signs of dehydration (too little fluid in the body): dry mouth, little or no urine, sunken eyes, dizziness on standing.
Signs of low blood sugar: shaking, sweating, hunger, confusion. Treat with sugar and call your doctor.
Go to an emergency department for swelling of the lips, tongue or throat, or for trouble breathing after taking guava. These are signs of a severe allergic reaction.
In the United States and the United Kingdom, guava fruit is an ordinary food and guava leaf products are sold as dietary or food supplements. They are not approved as medicines, and no health claims are authorised. In Mexico, a standardised guava leaf product is registered as a herbal medicine for diarrhoea.
Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.
Reviewed by the HealisticMD editorial team How we grade evidence →
What it is typically used for, usual dose, cautions, and the study behind it where real trial data exists.
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