Pau d'arco (also known as taheebo, lapacho, or ipe roxo) is a broad-leafed tree native to the tropical rain forests of Brazil. Growing up to 40 meters in height, pau d'arco has red to purple colored flowers, which bloom profusely shortly before the new leaves appear. The tree has extremely hard wood, which is used for lumber in the construction industry. The bark is used for health promoting purposes.
The active constituents in pau d'arco bark are a group of napthaquinone derivatives, including lapachol and other closely related compounds. The bark also contains compounds known as cyclopentene dialdehydes.
Dosage recommendations for pau d'arco vary according to intended use. A common recommendation is 1 gram of whole herb, in capsules or prepared as a tea, once or twice per day with meals. Pau d'arco appears to be well tolerated at this dosage range. High amounts of lapachol have been associated with side effects such as severe nausea, vomiting, anemia, and bleeding. Many herbalists recommend whole bark preparations over isolated lapachol because they are not associated with serious side effects. Pau d'arco is not recommended for pregnant women or nursing mothers.