BT-096 · Bignoniaceae

Pau d’arco

Handroanthus impetiginosus

Evidence: TraditionalCautionOverharvested

The tree covers its bare branches with pink flowers in the dry season and is among the national trees of Brazil and Paraguay.

In short

What is Pau d’arco?

Pau d’arco (Handroanthus impetiginosus) is a plant of the Bignoniaceae family. Traditions that use it: Amazon. Part used: inner bark.

Traditional use: The inner bark is boiled for fever, infections and skin disease. Scientific evidence: traditional. Contains lapachol.

Safety label: caution. High doses can cause nausea, vomiting and bleeding. Do not use with blood thinners.

Amazon and South America

The inner bark is boiled for fever, infections and skin disease.

Today

It has been marketed with claims of treating cancer; these are unproven.

Where it grows: Dry and humid forests of South America, from the Amazon to Argentina.
Harvest season: Bark is collected all year.
Local names: No Turkish folk name. Local names: pau d’arco, tahibo, lapacho

Some bark on sale comes from other species or from the outer bark.

The inner bark is boiled.

Contains lapachol. A 1970s cancer study was stopped because effective doses caused toxic side effects.

Caution

High doses can cause nausea, vomiting and bleeding. Do not use with blood thinners.

Medicine or substance	Why it matters
Blood thinners and antiplatelet drugs	Lapachol counteracts vitamin K; risk of bleeding.

This list is not complete. If you take regular medication, ask your pharmacist or doctor before trying Pau d’arco.

CITES: Appendix II (since 2022)
Note: Handroanthus species were listed in CITES Appendix II in 2022 because of illegal logging for their valuable wood.