Educational information, not medical advice — ask your doctor or midwife.
Palo Azul is the bark and heartwood of a small Mexican tree, Eysenhardtia polystachya. People simmer the wood chips into a light tea, most often for kidney and bladder comfort. It is a single herb from the African / Caribbean / Latin American tradition, not a blend.
The tea is famous for its colour. Held up to the light, the brew glows a soft blue, which is where the name "blue stick" comes from. It is usually drunk as a mild daily beverage rather than taken as a strong medicine.
Traditional users reach for it for painful urination, kidney stones, gout and high blood sugar. The human evidence is thin. Almost all research so far is laboratory and animal work, and a long history of traditional use tells you a plant has a long record, not that it works.
Palo Azul is also heavily marketed online as a way to "flush" drugs from your system before a urine test. No good evidence supports that claim, and you should not rely on it.
Nobody has shown clearly how Palo Azul works in people, so treat any explanation as a theory.
The wood contains plant pigments called flavonoids. In test tubes and in rats, some of these lower blood sugar and mop up reactive molecules that damage cells.
The tea also appears to act as a mild diuretic (it makes you pass more urine). That extra flushing is the usual explanation for its traditional use in urinary complaints, but it has not been measured properly in humans.
Palo Azul is sold in a few simple forms: - Loose wood chips or bark shavings for simmering into tea (the traditional form) - Pre-filled tea bags - Powdered bark in capsules - Liquid extracts and tinctures
The loose wood is the form with the longest track record. Capsules and extracts are modern products with no dosing research behind them.
Palo Azul has been used in Mexico since before European contact, and the tradition continues across Mexico and parts of Central America and the Caribbean today.
Spanish colonial writers recorded the blue-glowing wood as a remedy for kidney and bladder trouble, and it reached European apothecaries as "lignum nephriticum" (kidney wood). It remains a household tea in northern Mexico.
See a doctor promptly if you have severe or one-sided back or side pain, blood in your urine, burning when you pass urine, fever or chills, or if you cannot pass urine at all. These can signal a kidney stone or an infection that needs real treatment.
Get medical help the same day if you feel shaky, sweaty, confused or faint, which can mean your blood sugar has dropped too low. Also see a doctor if swelling in your legs or face keeps coming back, or if your symptoms have not improved after about two weeks of tea.
Stop straight away and seek care if you develop a rash, swelling of the face or lips, or trouble breathing.
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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