Herb library · Herb · Zea mays (styles and stigmas)
Corn silk
The fine threads of the corn ear, brewed as a tea for minor urinary complaints. No clinical trials have tested that use; a few small studies have looked at blood pressure and blood sugar.
Traditional use
Corn is a plant of the Americas, and its silk has long been brewed as a household tea for the urinary tract in North America and Europe; in Southeast Asia it is regarded as a source of potassium salts. In Europe a corn silk decoction is used alongside plenty of fluids for minor urinary tract complaints, a use the European Medicines Agency's draft assessment accepts on the basis of long-standing use. A 2016 case report described a corn silk decoction, passed down from a Native American grandmother, taken for bedwetting. It was also food: among the Chippewa (Ojibwe), Frances Densmore recorded (1928) "corn hair" dried and put in broth, and on the Missouri River Melvin Gilmore recorded (1919) that the Nebraska tribes ground dried silks with parched corn to sweeten it.
What studies show
- Insufficient
Minor urinary complaints: there are no clinical trials of corn silk alone for this use, and no well-designed trials of its effect on urine flow. The draft EMA assessment rests on long-standing use.
- Limited
Blood pressure: a 2019 review of 5 randomized trials (567 people) found only limited evidence, because of the trials' quality, that corn silk tea taken with blood pressure medicines might lower blood pressure more than the medicines alone.
- Insufficient
Blood sugar: a small study in 18 healthy volunteers found no added effect on blood sugar or insulin after meals.
Be careful of
Cautions
- ConditionDrink enough fluid while using it, and do not use it if a doctor has told you to limit fluids. See a doctor if you develop fever, painful urination, cramps or blood in the urine, or if symptoms last longer than 2 weeks.
- InteractionNo interactions have been reported. Because it has been studied alongside blood pressure medicines, tell your clinician if you take them.
- NoteNo clinical safety trials exist. Do not use it if you are allergic to it. One report described muscle inflammation in a man taking corn silk with several medicines and supplements; whether corn silk played a part is unknown.
- PregnancySafety in pregnancy and breastfeeding has not been established, and the draft EMA assessment does not recommend it then. Use in children under 12 has not been established.
- Ask a clinicianTalk with a clinician or pharmacist before using this if you take prescription medicines, are pregnant or breastfeeding, or are giving it to a child.
From the old books
What herbals and dispensaries of the past printed. History, in their words.
“The silk of corn (called “corn hair”) was dried before the fire and put in broth to season it. The corn silk was said to thicken the broth slightly as well as to impart a pleasing flavor.”
“Corn silks were gathered and, after being dried in the sun, were stored away for use as food. To this end the dried corn silks were ground with parched corn, and, it is said, gave sweetness to the compound.”
“In southern France, the inhabitants use it as a domestic remedy for calculi, gravel, and strangury.”
Sources
- European Union herbal monograph on Zea mays L., stigma (draft) (opens in a new tab) · EMA · read September 25, 2026
- Assessment report on Zea mays L., stigma (draft) (opens in a new tab) · EMA · read September 25, 2026
Reviewed September 25, 2026.