A THOUSAND YEARS AGO, the Incas of Peru found the inner bark of the pink-flowered lapacho tree indispensable for treating fever, sore throat, dysentery, snakebite, bladder and yeast infections, and even cancer. They also used its wood to make bows for hunting. Now called pau d’arco (pow-DAR-co), which is Portuguese for “bow stick,” the term refers to various trees of the Tabebuia family that grow in the mountains of Brazil, Argentina, Bolivia, Paraguay, and Peru.

In the 1950s, Brazilian researchers confirmed that this ancient medicine is indeed anti-bacterial. Among more recent investigations:

* A study at the University of Rio de Janeiro discovered that pau d’arco helps treat Staphylococcus aureus infections that resist antibiotics. Research at Seoul National University suggests that the herb is active against human intestinal bacteria, which cause food poisoning.

* Pau d’arco has certain anti-inflammatory and anti-viral activity, including against herpes I and II. It may reduce viral replication, according to a report in the Proceedings of the National Academy of Sciences.

* The herb is especially effective against Candida albicans, the fungus that causes vaginal yeast infections. Writing in the British Journal of Phytotherapy, Dutch herbalist Edward Oswald refers to the method of soaking a tampon in a strong pau d’arco tea while also taking the herb orally.
* Early reports declared pau d’arco to be useful in treating leukemia and other cancers, but the National Cancer Institute’s research into lapachol (the constituent with the most anti-tumor activity) was halted due to mild side effects. More recent lab tests in Korea determined that another constituent, beta-lapachone, kills cancer cells of the lung, colon, and prostate. Pau d’arco is some time away from being used to treat cancer, but the Incas may have been on the right track.

Dosage In tablets or capsules, 1 to 4 grams per day in divided doses–or 1 to 2 teaspoons of tincture three times a day. Consuming 1.5 grams per day or more may cause dizziness and GI upset, so consult your herbalist. Avoid pau d’arco if you’re taking anticoagulants or having surgery, or if you are pregnant or nursing.