Cathy Wong is a nutritionist and wellness expert. Her work is regularly featured in media such as First For Women, Woman's World, and Natural Health.

Arno Kroner, DAOM, LAc, is a board-certified acupuncturist, herbalist, and integrative medicine doctor practicing in Santa Monica, California.

Pau d'arco  (Tabebuia impetiginosa or Tabebuia avellanedae) is an herbal supplement made from the inner bark of several species of Tabebuia trees that grow in the Amazonian rainforests of Brazil as well as rainforests of Central and South America. In herbal medicine, the bark have been used centuries to treat a wide range of medical conditions.

Now widely available in dietary supplement form, pau d'arco extract contains a potent antioxidant known as quercetin thought to influence health. Pau d'arco is also rich in naphthoquinones , plant-based compounds that have antibacterial, antiviral, and antifungal effects.

Pau d'arco ("bow tree" in Portuguese) is so named because it is used by the native people of Brazil to make bows and arrows. The tree is also known as taheebo and ipé roxo. The inner bark can be made into a tea called lapacho.

This article looks at the many uses of pau d'arco in traditional and herbal medicine, including what the current research says. It also explains how to use pau d'arco safely and some of the side effects and risks associated with this ancient folk remedy.

This video has been medically reviewed by Meredith Bull, ND.

In folk medicine, pau d'arco is used to treat a wide range of medical disorders, including anemia, asthma, bronchitis, diabetes, eczema, enlarged prostate, influenza, intestinal worms, sexually transmitted infections, skin infections, urinary tract infections, and even cancer. The evidence supporting these claims is generally lacking.

With that being said, there is some evidence that pau d'arco can aid in the treatment of certain conditions. Here is a look at some of the key findings:

Pau d'arco may help fight inflammation, according to a study published in the Journal of Ethnopharmacology. The investigation, involving lab mice with medically induced edema (tissue swelling), demonstrated that a water-based extract of pau d'arco was able to block the production of pro-inflammatory compounds known as prostaglandins .

Prostaglandins are produced at sites of tissue damage or infection, causing inflammation, pain, and fever as part of the healing process. By countering this effect, pau d'arco may be able to reverse swelling and pain associated with inflammatory conditions such as osteoarthritis, rheumatoid arthritis, and benign prostatic hyperplasia (enlarged prostate).

To date, there have been few studies investigating the use of pau d'arco in treating any of these inflammatory disorders.

The Tabebuia tree has several unique properties. Among them, the bark is highly resistant to rotting, mold, and other common tree pathogens. It has long been assumed that these properties may be beneficial to humans, either by preventing or treating common bacterial, viral, or fungal infections.

Scientists have been able to isolate compounds in pau d'arco called naphthoquinones, including two known as lapachol and beta-lapachone that are able to kill a wide range of microorganisms.

A 2013 study from Brazil found that lapachol was able to neutralize a number of disease-causing bacteria in test tubes, including potentially serious ones like Enterococcus faecalis, Staphylococcus aureus, Cryptococcus gatti, and Paracoccidioides brasiliensis.

Similar studies have suggested that it may do the same with viruses associated with the common cold (adenoviruses), flu (influenza viruses), and cold sores (herpes simplex virus).

An early study published in the Journal of Ethnopharmacology also found that pau d'arco was effective in neutralizing Candida albicans (the fungus that causes oral thrush and vaginal yeast infections).

Despite the positive findings, the doses used in many of the test tube studies would be toxic in humans. Further investigation is needed.

As bold as the claim may seem, compounds in pau d'arco are believed to inhibit the growth of tumors, at least in the test tube.

In a review of studies published in the Journal of Ethnopharmacology, scientists concluded that the beta-lapachone found in pau d'arco was able to trigger apoptosis (programmed cell death) in certain types of cancer cells.

By way of background, all normal cells undergo apoptosis so that old cells can be replaced with new cells. Cancer cells, however, are "immortal," replicating without end. By triggering apoptosis, cancerous tumors can theoretically be controlled or reversed.

Although there is no evidence that pau d'arco extracts can prevent or treat cancer, the research does hint at a possible avenue for cancer drug development in the future.

Some people believe that pau d'arco can treat a wide range of infectious diseases, inflammatory conditions (like arthritis or enlarged prostate), and even certain cancers. To date, there is no evidence that pau d'arco can prevent or treat any medical condition.

Little is known about the long-term safety of pau d'arco. Common side effects include dizziness, nausea, vomiting, and diarrhea. The risk and severity of side effects tend to increase with the dose.

When taken in doses larger than 1.5 grams (1,500 milligrams), pau d'arco can become toxic and cause kidneys or liver damage. Overuse of pau d'arco can lead to severe vomiting, abdominal pain, fainting, and bloody stools.

Pau d'arco may slow blood clotting and increase the risk of bleeding during and after surgery. Stop using pau d'arco for at least two weeks before undergoing any type of surgical procedure.

Because pau d'arco can slow blood clotting, it should not be used with blood thinners like Coumadin (warfarin) or Plavix (clopidogrel).

The same applies to nonsteroidal anti-inflammatory drugs like Advil (ibuprofen), Aleve (naproxen), and Voltaren (diclofenac) in which the use of pau d'arco may increase the risk of stomach bleeding and ulcers.

Due to the lack of safety research, pau d'arco should not be used in children, pregnant women, or nursing mothers. It should also be used with caution in people with kidney or liver disease.

To avoid interactions or potentially serious side effects, always advise your healthcare provider about any herbal supplement or traditional medication you are taking.

Common side effects of pau d'arco include dizziness, nausea, vomiting, and diarrhea. At higher doses, pau d'arco can cause liver or kidney damage. Pau d'arco should be avoided if you use blood thinners or nonsteroidal anti-inflammatory drugs as it may increase the risk of bleeding.

Pau d'arco is available as capsules, tablets, dried bark tea, bark powder, and alcohol-based tinctures. There are no guidelines directing its appropriate use. Most pau d'arco supplements are sold in 500- to 550-milligram capsules are considered safe within this range. As a general rule, never exceed the dose printed on the product label.

Less certain is the safety of pau d'arco bark since you are unable to control the dose. To be safe, add no more than one level teaspoon of dried pau d'arco powder to one cup of hot water to make a tea. Strain the tea before drinking and discard the leftover bark.

Pau d'arco supplements, tinctures, and powders can be readily found online and in a growing number of supplement stores and natural food shops. Unless you are an experienced herbalist, it is best to avoid dried bark chips.

There is no recommended dose for pau d'arco. Pau d'arco supplements in capsule form may be safer than teas, tinctures, or powders as you are better able to control the dose.

Dietary supplements are largely unregulated in the United States. Because of this, the quality of supplements can vary considerably. This is especially true with herbal remedies in which the active ingredient is imported from overseas. Without the routine testing of these products, you can never really know how safe they are or if they contain what they say they contain.

To better ensure quality and safety, opt for well-known supplement brands with an established market presence. While many vitamin manufacturers will voluntarily submit their products for testing by an independent certifying body (like U.S. Pharmacopeia, ConsumerLab, and NSF International), herbal remedy producers rarely do.

Certification of a supplement does not mean that it is effective. It only means that the product is pure and contains only what is listed on the product label.

Whatever pau d'arco product you buy, it is important to read the label carefully to ensure that it contains Tabebuia avellanedae or Tabebuia impetiginosa as an ingredient.

To better ensure purity and safety, choose supplements that have been certified by an independent authority like U.S. Pharmacopeia, ConsumerLab, or NSF International.

Pau d'arco is the bark of several species of trees native to the rainforests of Central and South America that is believed to have medicinal properties.

Some people believe that pau d'arco can prevent or treat a wide range of unrelated conditions, including anemia, arthritis, asthma, diabetes, eczema, enlarged prostate, respiratory or urinary tract infections, and even cancer. To date, there is little solid evidence to support the claims.

Pau d'arco may cause dizziness, nausea, diarrhea, or vomiting in some people. At higher doses, it can cause liver or kidney injury. Due to the lack of safety research, pau d'arco should not be used in children or people who are pregnant or breastfeeding. It should also be avoided if you take blood thinners or nonsteroidal anti-inflammatory drugs.

Despite suggestions that pau d'arco may be active against breast cancer and prostate cancer cells, there is no evidence of any such effect in humans. To date, the research has been limited to test-tube studies and a few small animal studies.

Pau d’arco may relieve pain and inflammation from arthritis and help to reduce swelling from benign prostatic hyperplasia. It may help to prevent bacterial, viral, or fungal infections and treat yeast infections. However, more research is needed before pau d’arco can be recommended for preventing and treating any condition. 

Some animal studies suggest that pau d'arco can treat obesity by preventing the accumulation of fat-storage cells called adipocytes. Even so, there have been no studies in humans demonstrating such an effect.

The popularity of pau d'arco in traditional medicine has lead to concerns about the sustainability of the species. As a canopy tree of the Amazon, it is one of many species facing extinction as deforestation continues to reap havoc on the rainforests of Brazil. A related species, known as Tabebuia guayacan, is already on the threatened species list.

Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life.

Thank you, {{form.email}}, for signing up.

There was an error. Please try again.

Zhang M, Swarts SG, Yin L, et al. Antioxidant properties of quercetin. Adv Exp Med Biol. 2011;701:283-289. doi:10.1007/978-1-4419-7756-4_38

Gómez Castellanos JR, Prieto JM, Heinrich M. Red Lapacho (Tabebuia impetiginosa)--a global ethnopharmacological commodity? J Ethnopharmacol. 2009;121(1):1-13. doi:10.1016/j.jep.2008.10.004

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(1):145-152. doi:10.1016/j.jep.2008.06.016

Jiménez-González FJ, Veloza LA, Sepúlveda-Arias JC. Anti-infectious activity in plants of the genus Tabebuia. Univ Sci. 2013;18(3):257-267. doi:10.11144/Javeriana.SC18-3.aapg

Souza MA, Johann S, Lima LAR dos S, et al. The antimicrobial activity of lapachol and its thiosemicarbazone and semicarbazone derivatives. Mem Inst Oswaldo Cruz. 2013;108(3). doi:10.1590/S0074-02762013000300013

Portillo A, Vila R, Freixa B, Adzet T, Cañigueral S. Antifungal activity of Paraguayan plants used in traditional medicine. J Ethnopharmacol. 2001;76(1):93-98. doi:10.1016/s0378-8741(01)00214-8

Mohammad RM, Muqbil I, Lowe L, et al. Broad targeting of resistance to apoptosis in cancer. Semin Cancer Biol. 2015;35 Suppl:S78-S103. doi:10.1016/j.semcancer.2015.03.001

Kaur G, Verma N. Nature curing cancer - review on structural modification studies with natural active compounds having anti-tumor efficiency. Biotechnol Rep (Amst). 2015;6:64-78. doi:10.1016/j.btre.2015.01.005

Mukherjee B, Telang N, Wong GYC. Growth inhibition of estrogen receptor positive human breast cancer cells by Taheebo from the inner bark of Tabebuia avellandae tree. Int J Mol Med. 2009 Aug;24(2):253-60. doi:10.3892/ijmm_00000228

Zhang J, Hunto ST, Yang Y, Lee J, Cho JY. Tabebuia impetiginosa: a comprehensive review on traditional uses, phytochemistry, and immunopharmacological properties. Molecules. 2020 Sep;25(18):4294. doi:10.3390/molecules25184294

Iwamoto K, Fukuda Y, Tokikura C, Noda M. The anti-obesity effect of Taheebo (Tabebuia avellanedae Lorentz ex Griseb) extract in ovariectomized mice and the identification of a potential anti-obesity compound. Biochem Biophys Res. 2016;478(3). doi:10.1016/j.bbrc.2016.08.081

Thank you, {{form.email}}, for signing up.

There was an error. Please try again.