The idea of eating tree bark may sound disgusting, but you already do so and you probably enjoy it… cinnamon.
In a similar way, what pau d’arco tastes like is sweet and less woodsy. As with most teas, it can be slightly bitter due to the naturally occurring tannins, though many liken it to a licorice flavor. Not everyone will fall in love with the first cup, but after a few it will likely become an acquired taste.
And just like there are side effects of cinnamon, too much pau d’arco isn’t good for you, either.
Due to its alleged medicinal uses, people in Central and South America have drank it for over a thousand years. Their other names for the tea, lapacho or taheebo, have been hailed as “one of the primary medicines” that the Callawaya tribe used throughout its history (1).
What is pau d’arco?
It’s a Portuguese name, but how to say it in English is not that hard. The correct pronunciation of pau d’arco is pow-de-ah-co. How it’s pronounced can vary a bit by dialect.
The common name of this plant a trumpet tree, but not just any type. Pau d’arco only comprises a few species of the genus Tabebuia (syn. Handroanthus) (2). The type most often used is pink trumpet tea, or scientifically known as Tabebuia avellanedae tea (syn. Handroanthus impetiginosus).
This tree is not native to North America, though it is grown in the southern parts of California, Arizona, and Florida. You will find them throughout, Mexico, Central America, and the Caribbean, but their native homeland is South America, particularly in Paraguay and Argentina. Fully mature, it can reach heights of up to 125 feet, however that requires an ideal climate. Those growing in Los Angeles average just 30 feet tall (3).
What pau d’arco tea is made from is the inner bark, known as the phloem (pronounced floam). Branches of wild Tabebuia avellanedae trees are harvested, cut open, and the phloem is shaved off. These shavings are then used to brew herbal tea which does not have caffeine. Locals call it lapacho tea, or their word for the inner bark, which is taheebo.
Given that it’s such a niche product, don’t expect to find USDA certified organic tea for sale. It will be non-GMO though. Since it comes entirely from a tree, that means it’s vegan and gluten free.
Pau d’arco benefits
A detailed analysis of minerals, vitamins, and phytonutrients for this beverage isn’t found in the USDA National Nutrient Database. Tea manufacturers don’t include their own nutrition facts for pau d’arco either, because they only market it as a dietary supplement (that means they have supplement facts, which aren’t as detailed).
Aside from brewing it as a beverage, you can also buy liquid extract, powder, and capsules. The liquid and tincture forms are sometimes called essential oils, but they’re technically not an oil.
According to the NIH’s MedlinePlus entry about this tea and other supplement forms, there is “insufficient evidence to rate effectiveness for” the following uses of pau d’arco (4):
- Infections – yeast infections, bladder infections, intestinal worms, cold, flu, STDs
- Digestive disorders – diarrhea, ulcers, stomach and liver problems
- Lung disease – asthma, bronchitis
- Skin – boils
- Pain – arthritis
- Cancer
- Diabetes
In short, there is no proof of it currently working for anything. It should not be used to treat, cure, or prevent any disease.
As it stands today, let’s review the current scientific research so you can better decipher between the “magical properties” being claimed and what the studies have really found about killing candida yeast, cancer cells, and the other claimed benefits.
And just like you have people hyping it, you also have some hating it.
Herbalist Susun Weed says to “please stop drinking it” because it “will kill gut flora” and to not use it as a douche “or anything else” because “douches cause vaginal infections!” (5)
Is pau d’arco safe to drink? Without throwing Susun Weed under the bus, let’s just take a good hard look at the facts and findings, so you can decide for yourself.
Side effects
In the United States, a generally recognized as safe (GRAS) validation has not been pursued/approved, as it is not sold as a food ingredient. Even the tea is only available as a dietary supplement.
Some manufacturers advise consulting your healthcare practitioner prior to use, such as this box from Traditional Medicinals brand. Mountain Rose Herbs pau d’arco has a similar disclaimer.
The capsules from Nature’s Sunshine only advise consultation “if you are taking blood thinning medications, or have a bleeding disorder” or are pregnant/nursing. Nature’s Way has a similar advisory.
The liquid extract from Now Foods says all that and it’s for adults only (keep out of reach of children).
When consumed in moderation and according to the instructions on a given package, side effects of pau d’arco are rare. With high dosages, these reactions are more likely:
- dizziness
- vomiting
- diarrhea
- internal bleeding
- interference with healthy blood clotting after surgery
- interactions with blood clotting and thinning medications
- pregnancy and breastfeeding dangers
Those are the side effects reported by Web MD and the University of Maryland Medical Center (6). Mayo Clinic does not have an entry for it.
Lapachol, which is a natural phenolic compound in the plant, is believed to be responsible for many of the beneficial things being studied. The flip side is that lapachol is toxic and may be the root cause (or a worsening factor) in the adverse reactions. When a dosage of pau d’arco equals more than 1.5 grams per day, the risk of them happening seems to be greater.
A big problem with the teas, capsules, and other supplements is that they only tell you the weight of the dried bark, not how much lapachol is in them. Since that can vary, it makes the possibility of overdosing even more of a concern.
How much pau d’arco?
How much to drink or take safely is a moving target. Using different extraction methods, there was a piece in the Brazilian Journal of Chemical Engineering where they measured how much lapachol there was in Tabebuia avellanedae tea and wood samples (7). These were the results…
| % lapachol in sample | |||
|---|---|---|---|
| Sample | 150 bar | 180 bar | 210 bar |
| wood B | 1.49% | 1.61% | 1.7% ± 0.1 |
| tea C | n/a | n/a | 0.08% ± 0.01 |
| tea D | n/a | n/a | 0.05% ± 0.02 |
As you see the wood, bark and roots contains a lot of lapachol – around 1.5 to 2%.
How much lapachol there was in the two brewed tea samples was 0.05 and 0.08%. Why so low? They said:
“The very low content is consistent with the fact that these teas are prepared from the inner bark of Tabebuia avellanedae, and this part of the tree is known to have a low lapachol content (Steinert et al., 1996)”
It seems drinking the teas are much safer than the whole inner plus outer bark. Still, that’s a large variance between those two samples; one is 60% higher than the other.
Another risk to consider is the quality – or lackthereof – of pau d’arco capsules. By shaving off more than just the inner bark, some suppliers may cut corners, literally.
That could lead to a much higher percentage of lapachol in the product, since the rest of the wood and outer bark contain a lot; up to 3,500% more according to the above test.
Powders and pills are more of a danger for overdosing. Since they’re so concentrated, it’s easier to take too much of them. The same could easily happen with teas that aren’t made using the pure inner bark.
The lesson? Integrity of supplier is very important. Pau d’arco reviews should be read. Brand or company should be trustworthy.
Pau d’arco cancer research
If you search in the NIH’s PubMed database for Tabebuia avellanedae and cancer you will only get around three dozen results. A decent amount, but really not that much.
Most importantly, none are clinical trials or human studies. All research so far only involves cultured cells and animals.
This is not some new discovery, either.
Way back in 1968 the following paper was published (8). Translated from Portuguese to English, here’s the title:
“Antitumoral and toxicological properties of extracts of bark and various wood components of Pau d’arco (Tabebuia avellanedae)”
It wasn’t for another 14 years until the suspected anti-cancer compounds were identified as being quinones, which is a name for a large class of compounds (9).
After that, it wasn’t until the new millennium when new research began to surface. Experiments came out involving cultured human cells for prostate cancer (10) (11), colon cancer (12), lung cancer (13), bladder cancer (14), leukemia (15), and others.
In theory, how pau d’arco works against the tumors is said to be due to the ß-lapachone. Some of the more recent research (2016) sums up this mechanism (16):
“…our findings indicated that ß-lap modulates Sp1 transactivation and induces apoptotic cell death through the regulation of cell cycle- and apoptosis-associated proteins.”
That was based on their experiments with melanoma (skin cancer). Here’s a graph showing what they observed:
G361 and SK-MEL-28 are melanoma cell lines. As you see, the percent of them alive went down as the dosage of ß-lapachone went up (using 1, 2 and 3 µM).
For the G361 melanoma cells, these photos show their morphological changes after 48 hours. As you see, their numbers decreased and some changed shape, becoming more rounded.
That Sp1 downregulation they mentioned mimics what others are saying. Not too long before that paper, another talked about the same happening in experiments using oral squamous cell carcinoma (lip and oral cavity cancer) (17).
Metastasis, which is the spreading of tumors from one area to another, was a focus of another recent study. With colorectal lung metastasis in mice that was treated with ß-lapachone, they claimed the following results (18):
“In the mouse experimental metastasis model, ß-lapachone significantly inhibited the lung metastasis of CT26 cells.”
Based on experiments with cultured breast cancer cells, Argentinian scientists suggested that combining photodynamic therapy/PDT (an approved treatment) with the unproven ß-lapachone might be a “potentially promising modality” that warrants further research (19) (20).
Tumors can’t grow without angiogenesis, which is the growth of new blood vessels to feed them. Might there be another type of lapachone in the plant that interferes with angiogenesis?
Researchers at Harvard and MA General Hospital screened 50,000 compounds, tested 86 of them in assays for further performance, and out of those they only selected 2, which they found to be non-toxic to zebrafish (21). The star compound of the experiment was dehydro-alpha-lapachone, which they said:
“…inhibits vessel regeneration, interferes with vessel anastomosis, and limits plexus formation in zebrafish. Furthermore, DAL [dehydro-alpha-lapachone] induces vascular pruning and growth delay in orthotopic mammary tumors in mice.”
This chart shows the anti-tumor effects observed in their mouse models. Compared to the saline water (blue line) the dehydro-alpha-lapachone (red line) had lower vascular volume, length, and diameter by day 4.
Regardless of which form of lapachone you’re talking about, unfortunately there have been very few animal studies done to date.
One found that the extract of pau d’arco benefits mice with tumors, by prolonging their lifespan (22).
Another mouse study reported disappointing results (23):
“The ß-lapachone extracted from the Tabebuia avellanedae showed no protective effect of lesions induced by azoxymethane in colon of mice.”
Those lesions are colon cancer, induced by the poison azoxymethane.
As far as the more promising findings, those in and of themselves are not that special. Soursop and frankincense cancer research are just two of many similar plant-derived examples. The problem is what works in laboratory well plates doesn’t always translate to living, breathing humans.
This could be like many other cytotoxic natural compounds which seem promising in the early days, but just don’t work in real life. Even if it does work, the dosage of pau d’arco extracts for cancer might be a dangerously high amount, perhaps even lethal.
That’s always the catch-22 with finding treatments for this horrible disease. There are many toxic chemicals which can kill cultured cancer cells when poured directly on them in a Petri dish, but that doesn’t mean the same amounts are safe to use in a body.
It’s wrong to claim this as a benefit. A lot more research is needed on this topic to know anything, one way or another.
Does pau d’arco kill candida?
Using this tea for gastrointestinal parasites is a trending topic in the herbal remedy realm. Yeast infections such as Candida albicans and valley fever are the most discussed. Antifungal and alkaline properties are two theories put forth for those.
Susun Weed obviously isn’t a fan, but you do read about a few who talk about how to use it as a douche after menstruation, or as an enema. Thankfully, those websites do not include photos as part of their instructions!
While not fungal in nature, small intestinal bacterial overgrowth (SIBO) and urinary tract infections (UTI) in both men and women are two others you hear.
Some talk about more general digestive uses of taheebo tea, which may be completely unrelated to yeast; gastritis, constipation, and leaky gut. Or vague claims like it’s a blood cleanser for “detox” and good for kidneys.
All of those claims are misleading. Science has not validated any of them to work or be safe.
How to get rid of SIBO without antibiotics is an understandable desire, but there is not a single entry within the 27,000,000+ pieces of medical literature on PubMed about that disease and the pink trumpet tree, or any other in the genus.
Outside of PubMed, all we saw was an article published in the medical journal Original Internist (March 2013 20(1):30-38). The title of the paper was “Select Herbals Proposed as Beneficial in the Eradication of Small Intestinal Bacterial Overgrowth.”
It’s not research, but rather just a paper written by one doctor who talks about pau d’arco along with herbs like dill, thyme, oregano, stinging nettle, and horsetail, as well as TCM extracts like stemona root (bai bu), wormwood and other flowers, fruits, leaves and roots. Her pitch for why pau d’arco inner bark might work is only two paragraphs and not compelling whatsoever. It’s mostly unrelated yapping.
Using the tea as a douche or enema internally is nowhere to be found in scientific literature, either.
The story is the same for those other allegedly beneficial uses. The exception is candida, which does have 3 pieces of research listed in PubMed…
Title: Antimicrobial potentials of some plant species of the Bignoniaceae family
Year: 1994
Authors: University of Ibadan, Nigeria
Four different Bignoniaceae plant species were tested (24):
- Tabebuia rosea – The rosy trumpet tree or pink poui. This is closely related but a different species than the commonly consumed pink trumpet tea (Tabebuia avellanedae).
- Jacaranda mimosifolia – Called jacaranda or the fern tree. It has blue flowers.
- Tecoma stans – A flowering perennial shrub known as yellow trumpetbush and yellow bells.
- Crescentia cujete – The national tree of St. Lucia is better known as calabash.
All four were tested in the lab against fungi, as well as gram-positive and gram-negative bacteria. It was said that:
“Extracts of both the leaves and stem bark of majority of plant species studied showed variable but remarkable broad spectrum antimicrobial activity. However, methanol extracts of Tecoma stans leaves was found to be effective against only Candida albicans at the concentrations employed.”
All four species demonstrated antifungal activity against candidiasis. For Tecoma stans, the yeast was the only thing it seemed to be effective against (no efficacy against bacteria). However, that species nor any of the others are brewed as teas. Tabebuia rosea would be the most closely related.
Title: Evaluation of the antifungal potential of Brazilian Cerrado medicinal plants
Year: 2009
Authors: Universidade de Brasília, Brazil
As with the Nigerian study, this one didn’t even test the species of pau d’arco for candida which is normally drank as tea. Instead of Tabebuia avellanedae, they tested Tabebuia caraiba, better known as Caribbean trumpet tree (25).
Other names for it include tree of gold and silver trumpet. It has bright yellow flowers but should not be confused with yellow pau d’arco tea, as that typically uses yet another species, Tabebuia serratifolia.
This was a fairly extensive piece of research.
First, the scientists screened 57 different plant extracts in well plates against two fungal infections; Candida albicans and Trichophyton rubrum. Out of those 57, they chose the 11 most promising to evaluate more closely. After a series of tests, it was concluded that:
“While none of the extracts from these plant species greatly inhibited growth of C. albicans, several extracts, especially those from K. coriacea, R. alpinia, S. adstringens and T. caraiba, were identified as having pronounced antifungal activities toward several strains of the most frequently isolated dermatophyte, T. rubrum”
As to why they had “pronounced antifungal” activity against T. rubrum but not candida, they speculated that the effectiveness may vary between species of a plant:
“It is interesting to note that some of the plant extracts that showed high antifungal activity against T. rubrum, were inactive against C. albicans. Fontenelle et al. (26) has tested an essential oil against C. albicans and the dermatophyte Microsporum canis and also found a different activity between the species. It is relatively common and indicates differences in the mode of action of antidermatophytes to anti-candida compounds.”
Note that their above reference was not about pau d’arco essential oil, but rather the essential oil of an unrelated plant (Lippia sidoides) and how its performance varied between species.
They also cite a 2000 Brazilian study (not on PubMed) which said the compound ethyl p-hydroxycinnamate, found in the Tabebuia (pau d’arco) genus of plants, which has reportedly shown activity against C. albicans fungi.
Title: Antimicrobial potential of some plant extracts against Candida species
Year: 2010
Authors: Universidade Estadual de Campinas, Brazil
The extracts of several South American medicinal plants were tested against candida in the lab (27). This is the only study which used pau d’arco liquid extract coming from the same species that most teas use, Tabebuia avellanedae.
The were 2 forms of extraction methods used; dichloromethane and menthol extract. Only the latter showed antifungal advantages, but it wasn’t the best performing.
The plant extracts that did best were these…
“The findings presented in this paper indicate that the extracts obtained from the selected plants had anti-Candida activity. Punica granatum [pomegranate] and Syzygium cumini [java plum] extracts exerted strong antifungal activity and can be a source for the development of new therapeutic agents, as they inhibited the growth of Candida.”
It’s worth mentioning that Lyme disease has not been studied whatsoever. That is caused by the bacterium Borrelia burgdorferi (not a fungus) from tick bites (28). The reason it’s important to point this out is because many online sources talk about pau d’arco for lyme disease and candida as if they’re related diseases, when they definitely are not!
For the cultured candida, that last study reported the Minimum Inhibitory Concentration (MIC) was 0.003 mg/mL. That was how much pau d’arco for candida growing in the well plates to be affected. 1 mL of water weighs 1 gram. So in other words, the pau d’arco dosage was 0.003 mg per gram of water.
A standard serving of tea is around 2 grams (2,000 mg) of dried leaves or powder, therefore it seems plausible that such a concentration might be occurring with some teas… or maybe not.
Remember, they only said a methanol extract of the inner bark was what led to that 0.003 mg/mL MIC. Tea is not made with a concentrated extract like that.
But most important of all, that study involved the bark diluted in water, which was tested in Petri-dish like environments. The medium used to grow them was sabouraud dextrose agar (sugar) and not cells from an animal or human.
Websites advising how much pau d’arco for candida are not doing so based on the facts. While it might have some inhibitory effect, humans with this infection have never been studied and even it were to work, it may require an unsafe dosage.
The bottom line is there is not sufficient evidence that pau d’arco is good for candida.
Anti-inflammatory
Lastly, a lot of claims have been purported about inflammatory-related conditions.
Blogs and message boards talk of using pau d’arco for joint pain, arthritis, and diabetes. Skin conditions worsened by inflammation like eczema, plaque psoriasis, and acne are also brought up as candidates for a pau d’arco lotion or topical gel.
Any claims about the plant being “shown to” or “proven” to help these things are false. It has not been studied for any of these diseases.
There’s a 1999 piece out of Germany where they said “some lapacho-derived compounds appear to be promising as effective antipsoriatic agents” because they might inhibit HaCaT cell growth (29). But it has not been studied for psoriasis in animals or humans.
A piece in 1999 was about Tabebuia roseoalba studied its extract on the paws of mice and concluded (30):
“The results show that the ethanolic extract of leaves from T. roseoalba, ß-amyrin, and stigmasterol can be promising agents for the treatment for gouty arthritis, hyperuricemia, and inflammation. Stigmasterol, ß-amyrin, and rutin contribute to the observed effects of the ethanolic extract of leaves from T. roseoalba.”
Although closely related, they were looking at a different species of Tabebuia. Even if it were the same, that’s just one mouse study. Far from being any sort of proof.
In 2013, neurobiologists at the University of Arkansas said ß-lapachone suppresses types of cells which “may be effective in the treatment of inflammatory diseases such as MS [multiple sclerosis]” but that’s just a theory based on experiments they did with mice (31).
Verdict?
At the end of the day, very little research exists and none of the claimed benefits have been proven. It’s fine to enjoy as a delicious caffeine-free herbal tea, but this ingredient should not be used for any sort of disease.
How to make pau d’arco tea
Unlike loose leaf and powdered teas which only take a few minutes to brew, an authentic cup of taheebo or lapacho will require boiling the inner bark wood for an extended period. Prepare using a stainless steel or glass pot.
- Combine 1 flat tablespoon of pau d’arco and 3 cups of water in pot.
2. Boil for 5 minutes.
3. Reduce heat and simmer for an additional 20 minutes.
4. Allow to cool
5. Pour through strainer into cup and enjoy.
The inner bark is the only ingredient in pau d’arco. Some people combine it with echinacea, essiac, cat’s claw, garlic, grapefruit seed extract or other ingredients, but those are not the traditional recipe.
Where to buy?
If you live outside South America, you won’t have many options. If you live in the UK, a specialty health store like the chain Holland and Barrett should have pau d’arco tea for sale. In the US though it’s less popular, so even specialty grocery stores are unlikely to stock it. Places like GNC and Vitamin Shoppe will only carry the capsules and even those may need to be special ordered. That’s why most people buy it online.
On Amazon you can buy cut and sifted bark from Frontier, which is a respectable spice company.
If you want the convenience of individual tea bags which are ready to brew, Traditional Medicinals sells the rare wild yellow version known as “amarelo” by the locals. Reviews are generally positive for it.
You can find this yellow version on Amazon.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.