Pau d'Arco

Also called lapacho, taheebo, Tabebuia impetiginosa, Tabebuia avellanedae, Handroanthus impetiginosus, pau d'arco bark.

Best grade D across 3 graded outcomes Botanical Last checked

The short answer

From 9 sources

Pau d'arco is the inner bark of Latin American Tabebuia trees, used traditionally for fever, infections and skin problems. Human evidence is thin: one 12-woman open-label study for period pain and two studies of multi-herb products. LiverTox records a fatal liver failure in a man who also used skullcap, and MSKCC warns it may add to blood thinners.

Every graded outcome on this page

3 rows · line = participants
  1. Grade DRecurrence of anal warts after surgical removalWart recurrencen 261
  2. Grade DOral mucositis during head and neck radiotherapyOral mucositisn 40
  3. Grade DMenstrual cramp pain and safety (primary dysmenorrhea)Period painn 12

Key facts

What it is
The inner bark of Tabebuia (also classified as Handroanthus) trees native to the Amazon and other parts of Latin America, traditionally used for fever, malaria, bacterial and fungal infections and skin diseases12
Human evidence
One 12-person open-label safety study of pau d'arco alone and two studies of multi-ingredient products; none compared pau d'arco alone with a placebo234
Liver case
LiverTox records a 28-year-old man who developed liver failure after 6 months of skullcap and pau d'arco, needed a liver transplant and died shortly after5
Agency safety reviews
No ODS, NCCIH, LactMed, Health Canada or EMA source covers pau d'arco; LiverTox mentions it only in that case report, and MSKCC's About Herbs monograph flags a possible bleeding risk with blood thinners568
Funding
The period-pain study was funded by an NPLEX research fellowship and an NIH (NCCIH) grant, not by a supplement maker2
Lab research
Bark extracts and compounds such as beta-lapachone show anti-inflammatory and anticancer activity in cell studies; toxicology results vary with dose and duration of use17

What it is

Pau d'arco is the inner bark of Latin American Tabebuia (Handroanthus) trees, sold as tea, capsules and extracts.

How it works

Proposed

Lab research attributes pau d'arco's anti-inflammatory activity to naphthoquinones such as lapachol and beta-lapachone, which inhibited prostaglandin E2 and COX-2 in cell studies. In lab enzyme work lapachol blocked vitamin K recycling in a way that resembles coumarin anticoagulants. None of these effects has been confirmed for pau d'arco supplements in people.1279

Forms, side by side

3 forms named in our sources. The rest show what our data holds, and say plainly where it holds nothing yet.

Pau d'Arco forms compared

3 forms
Pau d'Arco forms compared: 3 forms by 3 attributes. Empty cells are labelled No data yet, or Not graded in the evidence row.
3 formsInner bark capsulesBark tea and liquid extractsMulti-ingredient products containing lapacho
Absorption in peopleNo human absorption data in our sources.2No human absorption data in our sources.1No human absorption data in our sources.3
GI toleranceIn 12 women on 1,050 mg/day for 8 weeks, 9 reported an adverse event, mostly mild and none serious; 9 of 12 completed the study.2No human trial of pau d'arco tea or liquid extract in our sources.1Orasol Plus was well tolerated by 40 radiotherapy patients; the STET abstract does not report adverse events.34
Studied forMenstrual cramp pain (open-label safety study)Traditional use only; no human trials in our sourcesOral mucositis during radiotherapy and anal wart recurrence after surgery
  1. Inner bark capsules
    Absorption in people
    No human absorption data in our sources.2
    GI tolerance
    In 12 women on 1,050 mg/day for 8 weeks, 9 reported an adverse event, mostly mild and none serious; 9 of 12 completed the study.2
    Studied for
    Menstrual cramp pain (open-label safety study)
  2. Bark tea and liquid extracts
    Absorption in people
    No human absorption data in our sources.1
    GI tolerance
    No human trial of pau d'arco tea or liquid extract in our sources.1
    Studied for
    Traditional use only; no human trials in our sources
  3. Multi-ingredient products containing lapacho
    Absorption in people
    No human absorption data in our sources.3
    GI tolerance
    Orasol Plus was well tolerated by 40 radiotherapy patients; the STET abstract does not report adverse events.34
    Studied for
    Oral mucositis during radiotherapy and anal wart recurrence after surgery
Every cell holds data from a cited page; citation numbers link to the page that holds them.Scroll the table for every column

What the human research says

Human trials only, one row per outcome. The form line shows what each trial actually tested. Grades follow our evidence-grading policy.

Trial map

3 graded outcomes, largest study first

3 graded outcomes: 2 improved, 1 mixed. The largest, a 2010 randomized trial of 261 people on recurrence of anal warts after surgical removal, found an improvement.

1. Recurrence of anal warts after surgical removal: improved, 261 people13. Menstrual cramp pain and safety (primary dysmenorrhea): improved, 12 people3
2. Oral mucositis during head and neck radiotherapy: mixed, 40 people2

1Recurrence of anal warts after surgical removal

Improved · Grade D · RCT, 261 people, 2010

HIV-negative patients having anal condylomata removed surgically (139 product, 122 surgery alone)

Dose, result and source
Every graded outcome on this page, largest study first
OutcomeFoundPeopleStudyWho was studied
Recurrence of anal warts after surgical removalImproved261Grade D · RCT, 2010HIV-negative patients having anal condylomata removed surgically (139 product, 122 surgery alone)
Oral mucositis during head and neck radiotherapyMixed40Grade D · Open-label trial, 201540 consecutive adults with head and neck cancer receiving radiotherapy
Menstrual cramp pain and safety (primary dysmenorrhea)Improved12Grade D · Open-label trial, 2022Generally healthy women aged 18 to 45 with primary dysmenorrhea (12 enrolled, 9 completed)
Each circle is one graded outcome on this page, numbered from the largest study down, and placed by how many people it studied (log scale). It shows who was studied and what was found, not advice about your dose.

Every graded row

3 rows
Grade DRecurrence of anal warts after surgical removalWart recurrenceRecurrence 7.2% vs 27.1%RCT
n 261 · 2010

Improved Recurrence occurred in 7.2% (10/139) of the product group vs 27.1% (33/122) of the surgery-only group (P < 0.0001).

Design
RCT, n = 261, 2010
Population
HIV-negative patients having anal condylomata removed surgically (139 product, 122 surgery alone)
Form
STET, a multi-herb immunostimulant product; PubMed indexing lists Tabebuia with Andrographis, Echinacea, Uncaria, papaya and grapefruit
Dose
Not stated in the abstract
Duration
30 days after surgery; 6 months of follow-up
Source
Reference 4 · PubMed 19548899 (opens PubMed)
Grade DOral mucositis during head and neck radiotherapyOral mucositisMixedOpen-label trial
n 40 · 2015

Mixed 11 patients (27.5%) developed grade 2 and 4 (10%) grade 3 oral mucositis; none developed grade 4 and none stopped radiotherapy because of mucositis. The product was well tolerated. There was no comparison group.

Design
Open-label trial, n = 40, 2015
Population
40 consecutive adults with head and neck cancer receiving radiotherapy
Form
Orasol Plus, a swallowable lapacho-based solution (full formula not given in the abstract)
Dose
3 times a day (amount not stated in the abstract)
Duration
From the first day to the end of radiotherapy
Source
Reference 3 · PubMed 26451712 (opens PubMed)
Grade DMenstrual cramp pain and safety (primary dysmenorrhea)Period painPain lower vs baseline (no control)Open-label trial
n 12 · 2022

Improved Pain intensity fell significantly from baseline after the first dose, at 4 weeks and at 8 weeks (p < .01); pain interference, quality of life and hs-CRP changes were not significant. Nine of 12 reported an adverse event, mostly mild, none serious; most lab markers stayed within normal limits.

Design
Open-label trial, n = 12, 2022
Population
Generally healthy women aged 18 to 45 with primary dysmenorrhea (12 enrolled, 9 completed)
Form
Encapsulated Tabebuia avellanedae inner bark (350 mg per capsule, with 25 mg rutin)
Dose
1,050 mg/day
Duration
8 weeks
Source
Reference 2 · PubMed 36960315 (opens PubMed)

What the numbers add up to

Each point is worked out from the data and the sources numbered on this page, with the arithmetic shown under it. It adds no new data and is not medical advice.

No placebo-controlled test of pau d'arco alone

The only study of pau d'arco by itself had 12 participants and no control group, and the one controlled trial compared a multi-herb product with surgery alone, so our sources cannot show what pau d'arco itself does.234

How we got this: Designs and interventions of the three cited human studies

Studied doses

Doses used in research, shown against the official limits. They describe the studies, not a recommendation for you.

Studied doses in research, not advice. These are amounts used in research, not personal advice. Your clinician or pharmacist can say what fits you.

Doses studied in human trials

Doses studied in human trials ranged from unstated amounts in multi-herb products to 1,050 mg a day of encapsulated inner bark for 8 weeks, the only single-ingredient dose tested (in 12 women).234

Interactions and safety

Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.

What Pau d'Arco meets

1 cited row 3 tested together

Medicines 1

Pau d'Arco1 medicine · 3 supplements

Supplements and foods 3

  • Reference summary
  • Tested together in a graded trial
Also cited: 3 tested together

  1. Anticoagulants and antiplatelet drugs

    • ReviewReference summary

      Anticoagulants and antiplatelet drugs, for example warfarin, aspirin, clopidogrel: MSKCC advises against combining pau d'arco with anticoagulant or antiplatelet drugs because it may increase their activity and the risk of bleeding; clinical relevance is not known. In lab enzyme studies lapachol inhibited vitamin K epoxide reductase, the enzyme warfarin acts on.

      Source 8, Memorial Sloan Kettering Cancer Center (About Herbs) (2023); Source 9, Arch Biochem Biophys (1984)

  2. AndrographisAndrographis page

    • Tested together

      Recurrence of anal warts after surgical removal. Graded on the Pau d'Arco page; tested together is not a claim that they work better together.

  3. EchinaceaEchinacea page

    • Tested together

      Recurrence of anal warts after surgical removal. Graded on the Pau d'Arco page; tested together is not a claim that they work better together.

  4. RutinRutin page

    • Tested together

      Menstrual cramp pain and safety (primary dysmenorrhea). Graded on the Pau d'Arco page; tested together is not a claim that they work better together.

Rows as our evidence profiles cite them; links stay on this site. Line weight shows what backs a row, not how serious an interaction is. No line means none was found in our sources, not that a combination is safe. Not medical advice: ask your pharmacist.

Interactions

1 agent
Published interactions, grouped by kind
AgentWhat the source saysEvidence
Medicines1
Anticoagulants and antiplatelet drugse.g. warfarin, aspirin, clopidogrelMSKCC advises against combining pau d'arco with anticoagulant or antiplatelet drugs because it may increase their activity and the risk of bleeding; clinical relevance is not known. In lab enzyme studies lapachol inhibited vitamin K epoxide reductase, the enzyme warfarin acts on.89Review

Check with what you take

Kept on this device only

Add what you take. We list every interaction our evidence profiles cite between Pau d'Arco and your picks, and between your picks.

Most cited:

Add a supplement or medicine you take to check it against Pau d'Arco.

Starting from one medicine? The interaction checker rates how serious each pair is, on a curated list of 19 entries for 11 medicines. This cabinet has no severity rating: it lists every interaction row our supplement pages cite.

Not medical advice, and no dosing advice. An empty result means no row we cite names that pair, by name or through a drug class we can link the medicine to, not that a combination is safe. Where our sources name only a group of medicines we cannot match, the cabinet says so. Ask your pharmacist before you combine supplements and medicines.

Who should be careful

4 groups
Liver
LiverTox records fatal liver failure (sinusoidal obstruction syndrome on the removed liver) in a 28-year-old man who used skullcap and pau d'arco together for 6 months. The case is listed in LiverTox's skullcap chapter; no agency source covers pau d'arco on its own.5
People on medicines
MSKCC advises against pau d'arco with blood thinners or antiplatelet drugs because of a possible added bleeding risk. NCCIH notes that dietary supplements may interact with medications and advises telling your health care providers about any supplement you use.86
Pregnancy, breastfeeding and children
No trial in our sources studied these groups. MSKCC reports that lapachol, a bark constituent, had fetotoxic and reproductive effects in animal studies, and NCCIH notes that many dietary supplements have not been tested in pregnant women, nursing mothers or children.86
Before surgery
Because of the possible bleeding risk with blood thinners (MSKCC), NCCIH's advice to tell your health care providers about all supplements well before an operation applies here.68
Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.

How to read the label

What to check on the Supplement Facts panel.

How to read the label

2 checks
Check the species and part

The one single-ingredient study used inner bark of Tabebuia avellanedae in 350 mg capsules that also held 25 mg rutin.2

Blends are different products

The mucositis and wart results come from multi-ingredient products, not pau d'arco alone.34

Have the bottle? Photograph its Supplement Facts panel and see each line, pau d'arco included, beside the doses and forms the trials used in Label X-Ray.

Frequently asked questions

Short answers to common questions; the numbers link to the sources below.

Common questions

6 answers
Does pau d'arco help menstrual cramps?

One open-label study in 12 women found pain scores fell from baseline over 8 weeks on 1,050 mg a day, but there was no placebo group and only 9 finished.2

Does pau d'arco fight infections or cancer?

Bark extracts and compounds such as beta-lapachone show anti-inflammatory and anticancer activity in cell studies, but no human trial in our sources tested these uses for pau d'arco alone. MSKCC notes that lapachol, an active constituent, had no clinical effect in people with chronic myelocytic leukemia.178

Is pau d'arco safe?

In the 12-woman study most side effects were mild. LiverTox records one fatal liver failure in a man who used pau d'arco with skullcap, and MSKCC lists nausea, vomiting and a possible bleeding risk with blood thinners. No government agency has reviewed pau d'arco itself.258

Does pau d'arco interact with blood thinners?

MSKCC advises against using it with anticoagulant or antiplatelet drugs because it may increase their effect and bleeding risk, though the clinical relevance is not known. In lab studies its constituent lapachol acted on the same vitamin K enzyme as warfarin.89

What is pau d'arco?

It is the inner bark of Latin American Tabebuia trees, also sold as lapacho or taheebo, used traditionally for fever, infections and skin diseases.123

What did the multi-herb studies find?

A lapacho-based solution was well tolerated during radiotherapy, and a multi-herb product cut anal wart recurrence (7.2% vs 27.1%) versus surgery alone. Neither isolates pau d'arco's effect.34

Sources

9 sources: trial abstracts, NIH fact sheets and reference databases. Numbers in the text link here.

Sources cited on this page

9 sources
  1. 1Tabebuia impetiginosa: A Comprehensive Review on Traditional Uses, Phytochemistry, and Immunopharmacological Properties.Review Molecules, 2020 · PMID 32962180
  2. 2Safety and tolerability of Pau d' Arco (Tabebuia avellanedae) for primary dysmenorrhea: A single-arm, open-label trial on adults ages 18-45.Open-label trial Adv Integr Med, 2022 · PMID 36960315
  3. 3Oral Lapacho-Based Medication: An Easy, Safe, and Feasible Support to Prevent and/or Reduce Oral Mucositis During Radiotherapy for Head and Neck Cancer.Open-label trial Nutr Cancer, 2015 · PMID 26451712
  4. 4Immunostimulation to reduce recurrence after surgery for anal condyloma acuminata: a prospective randomized controlled trial.RCT Colorectal Dis, 2010 · PMID 19548899
  5. 5Skullcap (LiverTox: Clinical and Research Information on Drug-Induced Liver Injury)Database National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), 2020 · ncbi.nlm.nih.gov
  6. 6Using Dietary Supplements WiselyFact sheet National Center for Complementary and Integrative Health (NCCIH), 2019 · nccih.nih.gov
  7. 7Anticancer potential and toxicity of the genus Handroanthus Mattos (Bignoniaceae): A systematic review.Review Toxicon, 2022 · PMID 35998713
  8. 8Pau D'arco (About Herbs, last updated April 2023)Fact sheet Memorial Sloan Kettering Cancer Center (About Herbs), 2023 · mskcc.org
  9. 9Lapachol inhibition of vitamin K epoxide reductase and vitamin K quinone reductase.Lab study Arch Biochem Biophys, 1984 · PMID 6497379

What changed

Every dated change to this page: what changed, who made it and why.

Change log

2 entries
Dated changes to this page
DateChangeWho and why
definition, summary, key facts, how it works, interactions, who should be careful, FAQAdded the anticoagulant and antiplatelet interaction from MSKCC About Herbs (pau d'arco monograph, updated April 2023) with lab support for lapachol's vitamin K mechanism (PMID 6497379); added MSKCC's animal reproductive-toxicity finding to the pregnancy note, bleeding risk to the medicines and surgery notes, and one FAQ. PubMed searched for 2023–2026 human trials: none of pau d'arco found, so the evidence table is unchanged. Shortened the definition to 140 characters or fewer.Writer: Kymata Health EditorialTrigger: A–Z page audit
allInitial editorial evidence review. Every PMID checked against NCBI E-utilities esummary (title and year) and each cited abstract read; numbers taken from the abstracts (and, where noted, the full text for funding, product and participant details). Funding disclosed: the period-pain study was funded by an NPLEX fellowship and NCCIH grant K24AT011568; the two blend studies state no funding in their abstracts. Safety text uses LiverTox (skullcap chapter case report) and NCCIH's Using Dietary Supplements Wisely, as no ODS, NCCIH, LactMed, Health Canada or EMA source covers pau d'arco. Where to buy: no product links, because of pau d'arco's safety concerns.Writer: Kymata Health EditorialTrigger: new page

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