Palo Azul (kidneywood)

Common names:  Palo azul, palo cuate, palo dulce, palo dulce blanco, palo de los riñones, leño nefrítico, Lignum nephriticum, rosilla, taray, taray de México, vara dulce, varaduz, Coate, coahtli, coatillo, coatli, cojtle, sipariqui, urza.

Scientific name:  Eysenhardtia polystachya

Where it is found:  This small tree is native to Mexico and Southwestern North America

Parts of plant used:  wood, branches, and leaves.

How to use Palo Azul:  The wood chips and or leafy branches can be steeped or boiled in water to make tea.

When the wood chips are steeped in cold water for a few hours, they confer a blue hue to the water (hence one of its popular names in Spanish, palo azul or “blue stick”). This color can later change to red or amber, according to the incidence of the light. The Spanish physicians first recorded the intense blue fluorescence of kidney wood tea in the sixteenth century.

Uses:  This plant has been used medicinally for centuries and was well known to the indigenous peoples of Mexico and parts of Central America well before the European invasion. The Spaniards were the first Europeans to take this plant to their homeland where it quickly became very popular for the treatment of various urinary tract diseases (Martínez, 1989).

In Mexico, the wood is either placed in water and taken as a cold tea or the branches and leaves are decocted (boiled) in water and taken for various health problems. These include urinary infections, to improve urine flow (diuretic), against kidney inflammation (nephritis) and pain, against kidney stones, to lower fevers, to treat stomach problems (colics), and as a general tonic. The tea can also be added to the water for livestock and poultry to drink in order to prevent disease. The leaves of a related species, E. texana (Texas kidneywood) are macerated (soaked) in water and the cold tea is drunk to relieve kidney problems.

A study by Gutiérrez and Báez (2014) using diabetic mice showed that a kidneywood methanol-water extract possessed considerable antioxidant activity against free radicals or reactive oxygen species (ROS) that cause oxidative stress and inflammation. Additionally, the plant compounds showed anti-glycation, liver -protective and hypoglycemic (lower blood sugar levels) actions that could be potentially beneficial against type 2 diabetes.

Safety/Precautions:

• The safety of using kidneywood during pregnancy and lactation has not been established.

Before you decide to take any medicinal herb or herbal supplement, be sure to consult with your health care professional first. Avoid self-diagnosis and self-medication: Always be on the safe side!