Health Benefits of Pau D'Arco

Can Amazonian tree bark fight infection and inflammation?

Pau d'Arco
Blossoms of the pau d'arco tree.

CostaPPPR/Wikimedia Commons

Pau d'arco (Tabebuia impetiginosa or Tabebuia avellanedae) is a type of tree native to the rainforests of Central and South America. In herbal medicine, extracts of the bark have long been used to treat a wide range of medical disorders.

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 exert antibacterial, antiviral, and antifungal effects.

Pau d'arco ("bow tree" in Portuguese) is so named because it 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.

Health Benefits

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:

Inflammation

Pau d'arco may help fight inflammation, according to a 2008 study 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 inhibit 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 some of the 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.

Infections

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

Lab studies have been able to isolate compounds in pau d'arco known as naphthoquinones, including lapachol and beta-lapachone which appear to have potent antimicrobial effects. 

A 2013 study from Brazil reported that lapachol was able to neutralize a number of disease-causing bacteria in the test tube, including Enterococcus faecalis, Staphylococcus aureus, Cryptococcus gatti, and Paracoccidioides brasiliensis.

Similar investigations 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 1).

An early study published in the Journal of Ethnopharmacology also found that, of the 14 Paraguayan plants commonly used in traditional medicine, pau d'arco had the highest activity against fungi and yeasts, including Candida albicans (the fungus associated with oral thrush and vaginal yeast infections).

While this may suggest that pau d'arco can prevent or treat infections, the doses used in many of the test tube studies would be toxic in humans. Further investigations would be needed to evaluate the safety and effectiveness of pau d'arco in a real-world setting.

Cancer

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 induce 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, by contrast, are immortal, replicating without end and gradually supplanting normal cells with cancerous ones. By restoring apoptosis, cancerous tumors can theoretically be controlled or even reversed.

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

Possible Side Effects

Due to a lack of research, little is known about the long-term safety of pau d'arco. Commonly noted side effects include dizziness, nausea, vomiting, and diarrhea. The likelihood 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 damage to the kidneys or liver. 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 anticoagulants like Coumadin (warfarin) or antiplatelet drugs like Plavix (clopidogrel). The same may apply to nonsteroidal anti-inflammatory drugs like Advil (ibuprofen), Aleve (naproxen), and Voltaren (diclofenac) in which the combined use may lead to gastric bleeding and stomach 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 unforeseen side effects, always advise your doctor about any herbal supplement or traditional medication you are taking.

Dosage and Preparation

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 formulations and are considered safe within this range.

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 supplements stores and natural food shops. Unless you are an experienced herbalist, it is best to avoid dried bark chips.

What to Look For

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 of 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 the U.S. Pharmacopeia (USP) or ConsumerLab, herbal remedy producers rarely do.

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.

Other Questions

Are pau d'arco trees endangered?

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.

If you are environmentalist, you may want to consider using other natural therapies that have less impact on the Amazonian biosphere.

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