Known as lapacho colorado in Argentina and Paraguay and as ipe roxo in Brazil, is a good example of the lure of the exotic. This South American native has been used medicinally by several indigenous groups.  There are several species of Tabebuia, and most appear to be broad-leaved evergreen trees with very hard wood that resists decay. It may be difficult to determine precisely which species is being sold as pau d'arco tea.  Pau d'arco has a reputation for having been used by the Incas, although it is not native to the high Andes.

It is said to be useful against cancer, diabetes, rheumatism, and ulcers, as well as several other ailments.

Readers of The People's Pharmacy Guide to Home and Herbal Remedies have reported success in using it topically as a soak to cure fungus-ridden toenails.  Extracts have been used topically to treat Candida yeast infections.  Overall, however, the research on pau d'arco does not offer strong support for most of the medicinal claims made for it.

The part of the tree used is the inner bark, and the preparation made from it is sometimes termed taheebo. Pau d'arco, or taheebo, contains a number of quinone compounds, including the naphthoquinone lapachol and the anthraquinone tabebuin. These and related compounds are assumed to be the active ingredients.  La pachol has antibacterial activity, and a related compound fights off fungus and yeast.  Lapachol has demonstrated activity against malaria, a property that would certainly be useful for people in the areas where Tabebuia species grow wild.

Research in the 1950s and 1960s indicated that taheebo extract and lapachol could slow the growth of certain tumors. The National Cancer Institute subsequently tested lapachol for anticancer activity in humans, with disappointing results.  Some practitioners report anecdotes of marvelous cancer cures, but the Brazilian Cancer Society disavows its use.  In human trials, it was difficult to attain therapeutically active levels of lapachol with oral administration, and when levels did get high enough, most people suffered serious adverse effects such as nausea and vomiting. 

Taheebo extract has anti-inflammatory activity, at least in rats. Researchers have also found that it helps animals resist ulcers.  In laboratory studies on human blood cells, lapachol had immunosuppressant effects at higher doses and immunostimulant activity at low doses.

Standard dose has not been determined. 

Special Precautions:  Pregnant women should not take taheebo internally because there is no evidence of its safety, although it can provoke adverse reactions.  Pau d'arco should be discontinued before surgery because of the danger of excessive bleeding.