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Pau d'arco

Pau d'arco (Tabebuia avellanedae) is native to South America, where it has been used to treat a wide range of conditions, including pain, arthritis, inflammation of the prostate gland (prostatitis), fever, dysentery, boils and ulcers, and various cancers. As early as 1873, there were reported medicinal uses of pau d'arco.

Scientists have identified two active chemicals in pau d'arco. These chemicals are called naphthoquinones: lapachol and beta-lapachone. In lab tests, these chemicals killed some bacteria, fungi, viruses, and parasites. They also have anti-inflammatory properties, and may be effective against diseases such as osteoarthritis. But no one knows whether they will have the same effects in humans, and the dose required would have severe, toxic side effects.

Pau d'arco is sometimes used for the following conditions, although there is no evidence it works:

• Candidiasis (a vaginal or oral yeast infection)
• Herpes simplex virus
• Influenza
• Parasitic diseases, such as schistosomiasis
• Bacterial infections, such as brucellosis
• Cancer

Test tube and animal studies have looked at whether pau d'arco has any effect on cancer. These tests have shown mixed results. Even in studies where pau d'arco did reduce the number of cancer cells, the amounts used would be toxic to humans.

The same is true of some of the doses that might be needed to kill bacteria or viruses. For this reason, you should take pau d'arco only under your health care provider's supervision.

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Plant Description

The pau d'arco tree grows in the warm parts of Central and South America. It is a broad leaf evergreen that grows to a height of 125 feet and has pink-to-violet colored flowers. The tree's extremely hard wood makes it resistant to disease and decay. The inner bark of the tree is used medicinally. In recent years there has been an increasing demand for pau d'arco, causing the trees to become endangered.

What's It Made Of?

Most of the chemical research on pau d'arco has been done on the wood and not the inner bark. Pau d'arco contains chemical compounds called naphthoquinones, specifically lapachol and beta-lapachone. They seem to have antifungal, antiviral, and antibacterial properties. They also contain significant amounts of the antioxidant quercetin.

Available Forms

Pau d'arco is sold as tablets, dried bark tea, and tincture (which contains alcohol). The chemicals that give pau d'arco its medicinal effects don't dissolve well in water, so a tea is not recommended.

Most pau d'arco products are not standardized, so it is hard to determine whether or not they contain a safe amount of these active substances. It is important to read the label carefully to make sure that the product actually contains Tabebuia avellanedae as an ingredient.

How to Take It

Pediatric

DO NOT give pau d'arco to infants or children.

Adult

It is important to discuss the dose with your provider, since large amounts of pau d'arco can be toxic. The risk of side effects seems to be greater when the dose of lapachol is more than 1.5 g per day. However, it can be hard to determine how much lapachol the powdered bark contains.

Precautions

The use of herbs is a time-honored approach to strengthening the body and treating disease. Herbs, however, can trigger side effects, and can interact with other herbs, supplements, or medications. For these reasons, you should take herbs with care, under the supervision of a health care provider.

Talk to your provider to determine the proper dose of pau d'arco because too much can be dangerous.

At recommended doses, side effects are uncommon but may include anemia, nausea, diarrhea, and dizziness.

High doses can cause uncontrolled bleeding and vomiting.

Pregnant and nursing women should not take pau d'arco.

Possible Interactions

Antiplatelet and anticoagulant drugs (blood thinners)

Pau d'arco may affect the blood's ability to clot, and could interfere with blood-thinning drugs, including:

• Warfarin (Coumadin)
• Clopidogrel (Plavix)
• Aspirin

Supporting Research

Anesini C, Perez C. Screening of plants used in Argentine folk medicine for antimicrobial activity. J Ethnopharmacol. 1993;39:119-128.

Bang W, Jeon YJ, Cho JH, et al. B-lapachone suppresses the proliferation of human malignant melanoma cells by targeting specificity protein 1. Oncol Rep. 2016; 35(2):1109-16.

Byeon SE, Chung JY, Lee YG, Kim BH, Kim KH, Cho JY. In vitro and in vivo anti-inflammatory effects of taheebo, a water extract from the inner bark of Tabebuia avellanedae. J Ethnopharmacol. 2008;119:145-152.

Colman de Saizarbitoria T, Anderson JE, Alfonso D, McLaughlin JL. Bioactive furonaphtoquinones from Tabebuia barbata (Bignoniaceae). Acta Cient Venez. 1997;48:42-46.

de Miranda FG, Vilar JC, Alves IA, Cavalcanti SC, Antoniolli AR. Antinociceptive and antiedematogenic properties and acute toxicity of Tabebuia avellanedae Lor. ex Griseb. inner bark aqueous extract. BMC Pharmacol. 2001;1:6.

Dinnen RD, Ebisuzaki K. The search for novel anticancer agents: a differentiation-based assay and analysis of a folklore product. Anticancer Res. 1997;(2A):1027-1033.

Gomez Castellanos JR, Prieto JM, Heinrich M. Red Lapacho (Tabebuia impetiginosa) -- a global ethnopharmacological commodity? J Ethnopharmacol. 2009;121:1-13.

Kung HN, Yang MJ, Chang CF, Chau YP, Lu KS. In vitro and in vivo wound healing-promoting activities of beta-lapachone. Am J Physiol Cell Physiol. 2008;295:C931-C943.

Lee JI, Choi DY, Chung HS, et al. Beta-lapachone induces growth inhibition and apoptosis in bladder cancer cells by modulation of Bcl-2 family and activation of caspases. Exp Oncol. 2006;28:30-35.

Lee MH, Choi HM, Hahm DH, et al. Analgesic and anti-inflammatory effects in animal models of an ethanolic extract of taheebo, the inner bark of tabebuia avellanedae. Mol Med Rep. 2012;6:791-796.

Machado TB, Pinto AV, Pinto MC, et al. In vitro activity of Brazilian medicinal plants, naturally occurring naphthoquinones and their analogues, against methicillin-resistant Staphylococcus aureus. International Journal of Antimicrobial Agents. 2003;21:279-284.

Muller K, Sellmer A, Wiegrebe W. Potential antipsoriatic agents: lapacho compounds as potent inhibitors of HaCaT cell growth. J Nat Prod. 1999;62:1134-1136.

Park BS, Lee HK, Lee SE, et al. Antibacterial activity of Tabebuia impetiginosa Martius ex DC (Taheebo) against Helicobacter pylori. J Ethnopharmacol. 2006;105:255-262.

Pereira EM, Machado Tde B, Leal IC, et al. Tabebuia avellanedae naphthoquinones: activity against methicillin-resistant staphylococcal strains, cytotoxic activity and in vivo dermal irritability analysis. Ann Clin Microbiol Antimicrob. 2006;22:5.

Pereira IT, Burci LM, da Silva LM, et al. Antiulcer effect of bark extract of Tabebuia avellandae: activation of cell proliferation in gastric mucosa during the healing process. Phytother Res. 2013;27:1067-1073.

Pinto CN, Dantas AP, De Moura KC, et al. Chemical reactivity studies with naphthoquinones from Tabebuia with anti-trypanosomal efficacy. Arzneimittelforschung. 2000;50:1120-1128.

Portillo A, Vila R, Freixa B, Adzet T, Canigueral S. Antifungal activity of Paraguayan plants used in traditional medicine. J Ethnopharmacol. 2001;76:93-98.

Rakel D. Integrative Medicine. 3rd ed. Philadelphia, PA: Elsevier Saunders; 2012.

Robbers JE, Tyler VE. Herbs of Choice: The Therapeutic Use of Phytomedicinals. New York, NY: The Haworth Herbal Press; 1999:246-247.

Suo M, Isao H, Kato H, Takano F, Ohta T. Anti-inflammatory constituents from Tabebuia avellanedae. Fitoterapia. 2012;83:1484-1488.

Ueda S, Umemura T, Dohguchi K, et al. Production of anti-tumour-promoting furanonaphthoquinones in Tabebuia avellanedae cell cultures. Phytochemistry. 1994;36:323-325.

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Review Date: 1/1/2017  

Reviewed By: Steven D. Ehrlich, NMD, Solutions Acupuncture, a private practice specializing in complementary and alternative medicine, Phoenix, AZ. Review provided by VeriMed Healthcare Network. Also reviewed by the A.D.A.M. Editorial team.

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