Botanical names:
Tabebuia avellanedae, Tabebuia impetiginosa

Parts Used & Where Grown

Various related species of pau d’arco trees grow in rain forests throughout Latin America. The bark is used for medical purposes.

What Are Star Ratings?

Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.

For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.

3 Stars Reliable and relatively consistent scientific data showing a substantial health benefit.

2 Stars Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.

1 Star For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.

This supplement has been used in connection with the following health conditions:

Used for Why
1 Star
Refer to label instructions
Pau d’Arco is an herb that directly fights both microbes and fungus.

Herbs that directly attack microbes include the following: chaparral, eucalyptus, garlic, green tea, lemon balm (antiviral), lomatium, myrrh, olive leaf, onion, oregano, pau d’arco (antifungal), rosemary, sage, sandalwood, St. John’s wort, tea tree oil, thyme, and usnea.

1 Star
Refer to label instructions
Pau d’arco extract has been used traditionally for prostatitis. The herb exerts antibacterial activity against E.coli, the most common cause of two types of prostatitis.

Pau d’arco extract has been used traditionally for prostatitis.2 According to test tube studies, pau d’arco exerts antibacterial activity against E.coli,3 which suggests a possible mechanism for this claim. However, no scientific studies of the effectiveness of pau d’arco for preventing or treating prostatitis have been done.

Traditional Use (May Not Be Supported by Scientific Studies)

Native peoples in Central and South America reportedly use pau d’arco bark to treat cancer, lupus, infectious diseases, wounds, and many other health conditions.1 Caribbean folk healers use the leaf of this tree in addition to the bark for the treatment of backache, toothache, sexually transmitted diseases, and as an aphrodisiac.

How It Works

Botanical names:
Tabebuia avellanedae, Tabebuia impetiginosa

How It Works

Lapachol and beta-lapachone (known collectively as naphthaquinones) are two primary active compounds in pau d’arco. According to laboratory tests, both have anti-fungal properties as potent as ketoconazole, a common antifungal drug.4 However, amounts of these constituents needed to exert an antifungal effect may be toxic to humans. Although these compounds also have anticancer properties according to test tube studies, the effective amount for this effect may also be toxic.5 , 6 Therefore, pau d’arco cannot currently be recommended as a treatment for cancer.

How to Use It

A traditional recommendation is 2–3 teaspoons (10–15 grams) of the inner bark simmered in a pint (500 ml) of water for fifteen minutes three times per day.7 However, the naphthaquinones believed to give pau d’arco its major effects are very poorly extracted in water, so teas are not usually recommended in modern herbal medicine.8 Capsules or tablets providing 500–600 mg of powdered bark can be taken three times per day. A tincture, 1/8–1/4 teaspoon (0.5–1 ml) three times per day, can also be used.


Botanical names:
Tabebuia avellanedae, Tabebuia impetiginosa

Interactions with Supplements, Foods, & Other Compounds

At the time of writing, there were no well-known supplement or food interactions with this supplement.

Interactions with Medicines

As of the last update, we found no reported interactions between this supplement and medicines. It is possible that unknown interactions exist. If you take medication, always discuss the potential risks and benefits of adding a new supplement with your doctor or pharmacist.
The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a supplement with your doctor or pharmacist.

Side Effects

Botanical names:
Tabebuia avellanedae, Tabebuia impetiginosa

Side Effects

High amounts (several grams daily over several days) of lapachol can cause uncontrolled bleeding, nausea, and vomiting.9 Use of the whole bark is typically safer than isolated lapachol—side effects have included nausea and gastrointestinal upset.10 Pregnant or breast-feeding women should avoid use of pau d’arco.

One case report exists of a 28-year-old man who died of liver failure after taking unspecified amounts of pau d’arco, scullcap, and zinc.11 It appears likely that this may have been a case of adulteration of scullcap with germander.12


1. Duke JA. CRC Handbook of Medicinal Herbs. Boca Raton, FL: CRC Press, 1985, 470-1.

2. Pizzorno JE, Murray MT. A Textbook of Natural Medicine, 2nd ed.. New York: Churchill Livingstone, 1999, 968.

3. Anesini C, Perez C. Screening of plants used in Argentine folk medicine for antimicrobial activity. J Ethnopharmacol 1993;39:119-28.

4. Guiraud P, Steiman R, Campos-Takaki GM, et al. Comparison of antibacterial and antifungal activities of lapachol and beta-lapachone. Planta Med 1994;60:373-4.

5. Tyler VE. Herbs of Choice: The Therapeutic Use of Phytomedicinals. Binghamton, NY: Pharmaceutical Products Press, 1994, 180.

6. Oswald EH. Lapacho. Br J Phytother 1993/4;3:112-7.

7. Foster S. Herbs for Your Health. Loveland, CO: Interweave Press, 1996, 70-1.

8. Awang DVC, Dawson BA, Ethier JC, et al. Naphthoquinone constituents of commercial lapacho/pau d'arco/taheebo products. J Herbs Spices Med Plants 1994;2:27-43.

9. Duke JA. CRC Handbook of Medicinal Herbs. Boca Raton, FL: CRC Press, 1985, 470-1.

10. Oswald EH. Lapacho. Br J Phytother 1993/4;3:112-7.

11. Hullar TE, Sapers BL, Ridker PM, et al. Herbal toxicity and fatal hepatic failure [letter]. Am J Med 1999;106:267-8.

12. Brown D. A case of fatal liver failure associated with herbal products. Healthnotes Rev Complement Integrative Med 1999;6:176-7.