Educational information, not medical advice — ask your doctor or midwife.
Corn (Zea mays) is a grain crop, a daily food and a folk remedy. In Haiti it is called mayi, in Cuba maíz. The part used as medicine is the silk, the fine threads inside the husk.
Corn silk is dried and brewed as a tea. In Jamaica, corn silk tea is a common home drink for the bladder and kidneys. Caribbean households also used it for swelling and for bedwetting in children.
As food, corn is not in question. It is a safe staple for most people and has no gluten. Whole corn and cornmeal give starch, fibre and some B vitamins.
The medicinal claims are another matter. Human trials on corn silk are few, small and weak. Its effects as a remedy are not proven.
Today corn silk is sold as tea bags, capsules and tinctures. Labels point to fluid balance and urinary comfort. Those labels rest on tradition, not on strong trials.
Long use in a tradition is not proof that a remedy works. It is also not proof that it is safe.
No one has shown clearly how corn silk works in people.
In rat studies, corn silk extracts raised urine output. In cell and animal studies they also lowered blood sugar and blood fats. Whether any of that happens at tea strength in people is unknown.
Corn silk holds potassium. Some writers say this adds to its water-pill (diuretic) effect. That idea comes from lab and animal work, not from good human trials.
The tea also holds mucilage, a slippery plant fibre. Tradition says it soothes a sore bladder. This has not been tested well in people.
Corn itself acts as food, not as medicine. The fibre in whole corn feeds gut bacteria and adds bulk to stool. That effect is well accepted for fibre in general.
Corn silk tea is the main medicinal form.
You can find the silk loose and dried, in tea bags, or as a liquid tincture. Capsules and extracts are also sold.
Fresh silk from a corn cob is used at home in the Caribbean. It is pulled from the husk and steeped in hot water.
As food, corn comes as fresh cobs, cornmeal, hominy, grits, polenta and popcorn. Corn starch and corn oil are kitchen staples, not remedies.
Quality control is loose. Home-dried silk can carry mould or farm sprays. Packaged products vary in strength from brand to brand.
Maize came from the Americas and was grown there for thousands of years.
Caribbean households used corn silk tea for urinary problems, swelling and bedwetting in children. Haitian and Cuban kitchens treated maize as a daily food, as mayi and maíz. Jamaican home practice kept corn silk tea as a common kidney and bladder drink.
The plant moved around the world after 1492. Corn silk tea also appears in Chinese, Turkish and Latin American folk use for the same kinds of complaints.
Maize-only diets caused harm in the past. Where grain was not soaked in lime water, pellagra spread. Pellagra is a disease of niacin (vitamin B3) shortage.
Traditional nixtamalization, soaking grain in lime water, prevented that problem. It is a food practice, not a remedy.
Stop and get emergency help if your lips, tongue or throat swell, or if you wheeze or struggle to breathe. These can be signs of a serious allergic reaction.
See a doctor the same day for fever with back pain, blood in your urine, or severe pain in your side. Also seek care if you pass very little urine.
Book an appointment if swelling in your legs or face is new or getting worse. The same goes for breathlessness when lying flat, or for a child who starts wetting the bed again after being dry.
If you have diabetes and feel shaky, sweaty or confused, check your blood sugar and treat a low at once.
Corn is an ordinary food worldwide. In the United States corn silk is sold as a dietary supplement or herbal tea, not as an approved drug. In the UK and EU it is sold as a food supplement with no approved medical claims.
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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