Frequently Asked Questions

Pau d'Arco is a large canopy tree native to the Amazon rainforest and other tropical regions of South and Latin America. Botanically known as Tabebuia impetiginosa (or Handroanthus impetiginosus), it's known for vibrant pink and purple blossoms and exceptionally hard, durable wood.

The traditional and studied activity comes from the phloem — the thin inner bark layer. For centuries, indigenous tribes across South America have harvested this inner bark to create a therapeutic decoction, rooted in phytochemicals like lapachol and beta-lapachone that are the focus of modern research.

Pau d'Arco's studied activity centers on three broad areas:

• Antimicrobial activity — research in the Journal of Ethnopharmacology has looked at inhibition of certain bacteria and fungi.
• Anti-inflammatory effects — studies suggest active compounds may inhibit inflammatory signaling pathways like NF-κB. See Pau d'Arco and Inflammation.
• Traditional immune support — Pau d'Arco contains antioxidants studied for combating oxidative stress.

Nearly all of this is laboratory or animal-model research — see each linked article for the specific evidence tier.

Pau d'Arco has a long history of traditional use, but it's not risk-free for everyone. The most commonly reported side effects are mild GI upset or nausea, especially at high doses. It also contains compounds that may have a mild blood-thinning effect — see the drug interaction question below. Full breakdown: Pau d'Arco Side Effects and Safety.

We advise against using Pau d'Arco during pregnancy or while breastfeeding. Laboratory studies on isolated lapachol have suggested potential abortifacient properties in animal models. Whole-bark tea is chemically different from a concentrated isolate, but there are no human clinical trials confirming safety for developing fetuses or infants — so out of caution, we recommend avoiding it during pregnancy and nursing.

Pau d'Arco's active quinoids aren't highly water-soluble, so a simple steep under-extracts them — you need a decoction (simmering). Full step-by-step guide: How to Brew Pau d'Arco Tea Correctly.

This is the most important sourcing question. Outer bark contains very few active compounds and serves mainly as the tree's protection; the inner bark (phloem) is where the compounds concentrate. Products blending in outer bark or heartwood are diluted. Always look for “100% Inner Bark” on the label — see our Inner Bark Guide.

Pau d'Arco is best known in the wellness community for research into Candida albicans activity — lab studies have looked at how its compounds may disrupt yeast cell walls and biofilms. See Pau d'Arco and Candida for the specific research, and Pau d'Arco and Gut Balance for broader digestive support research.

Yes. Pau d'Arco contains naphthoquinones that may interact with:

• Blood thinners — Warfarin (Coumadin), Aspirin, or other antiplatelet drugs; risk of increased bruising or bleeding.
• Surgery — stop use at least two weeks before any scheduled surgery.

Always consult your healthcare provider before adding Pau d'Arco to your routine if you take prescription medication.

This deserves a direct answer: no, and we don't claim it does. Traditionally, healers in South America used Pau d'Arco for various conditions including forms of cancer, which led the National Cancer Institute to study the plant starting in the 1960s.

Laboratory research on beta-lapachone has shown antitumor activity against cancer cells in a petri dish — that's a very different thing from a treatment that works in a person. Human clinical trials on isolated lapachol produced side effects at the doses required, and robust human trials on the tea itself, in cancer patients, don't exist. We do not claim Pau d'Arco cures, treats, or prevents cancer.

If you're researching this because of a cancer diagnosis, please read the full evidence-tiered breakdown in Pau d'Arco and Cancer — and talk to your oncologist. This is never a substitute for professional medical care.