Health Care Professional Information

Scientific Name
Tabebuia impetiginosa, Tabebuia avellanedae, Tabebuia heptaphylla
Common Name

Ipe-Roxo, lapacho, purple lapacho, trumpet bush and taheebo

Clinical Summary

Pau D'arco is a tree native to South America, preparations derived from the bark of which have been traditionally used to treat bacterial, fungal, viral infections, and cancer. Quinones, the main constituents, were shown to be the active principle of Pau D'arco (11) (12) (13) (14).
In vitro and in vivo studies of compounds isolated from Pau D'arco demonstrated antibacterial (3) (4) (5) (6), antifungal (7), antipsoriatic (8), immunomodulatory (9) (10), anti-inflammatory (19), antidepressant (20), anticancer (11) (12) (13) (14) (25), and antimetastatic (14) properties. One of the compounds may also be effective against inflammatory disorders (24). A Pau D'arco extract selectively inhibits growth of ER positive breast cancer cells (21). Human studies are needed to validate these effects.

In a small single-arm study, Lapachol, a naphthoquinone isolated from the tree bark, failed to show any effects on patients with non-leukemic tumors or CML (chronic myelocytic leukemia) (15).
Reported adverse events from use of Pau D'arco include nausea, vomiting, dizziness and anemia (16). It may also enhance the activity of anticoagulants (17).

Purported Uses
  • Cancer treatment
  • Antibacterial
  • Antifungal
  • Quinone compounds: Lapachol, beta-lapachone, xyloidone (naphthoquinones) and tabebuin (anthroquinone)
  • Flavonoids: Quercetin
  • Glycosides: Iridoid, lignan, isocoumarin, phenylthanoid, phenolic
  • Cyclopentene dialdehydes

(1) (2) (3)

Mechanism of Action

The anticancer activity of beta-lapachone, a quinone compound isolated from Pau D'arco, may be due to down regulation of COX-2 (cyclooxygenase) and telomerase activities (11). Beta-lapachone also induces apoptosis in cancer cells via mitochondrial-signaling (12) or by activating caspases (3) (9)  (18). The anti-metastatic activity of beta-lapachone was shown to be through decreasing the invasive ability of cancer cells by inducing Egr-1 that is known to suppress metastasis (14).


Some constituents may have toxic effects. The effectiveness of Pau d'arco for the treatment of cancer in humans remains unproven.

Adverse Reactions
  • Reported: Nausea, vomiting, dizziness, anemia, bleeding, and discoloration of urine (16).
  • Short term administration of Lapachol caused reproductive toxicity (significant reduction in the weight of the seminal vesicle) in adult male rats (22).
  • Oral administration of Lapachol resulted in clastogenic effects in rats (23).
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  1. Warashina T, Nagatani Y, Noro T. Further constituents from the bark of Tabebuia impetiginosa. Phytochemistry. 2005;66(5):589-597.
  2. Koyama J, Morita I, Tagahara K, Hirai K. Cyclopentene dialdehydes from Tabebuia impetiginosa. Phytochemistry. 2000;53(8):869-872.
  3. Park BS, Lee HK, Lee SE, et al. Antibacterial activity of Tabebuia impetiginosa Martius ex DC (Taheebo) against Helicobacter pylori. J Ethnopharmacol. 2006;105(1-2):255-262.
  4. Anesini C, Perez C. Screening of plants used in Argentine folk medicine for antimicrobial activity. J Ethnopharmacol. 1993;39(2):119-128.
  5. Park BS, Kim JR, Lee SE, et al. Selective growth-inhibiting effects of compounds identified in Tabebuia impetiginosa inner bark on human intestinal bacteria.J Agric Food Chem. 2005;53(4):1152-1157.
  6. Pereira EM, Machado Tde B, Leal IC, et al. Tabebuia avellanedae naphthoquinones: activity against methicillin-resistant staphylococcal strains, cytotoxic activity and in vivo dermal irritability analysis. Ann Clin Microbiol Antimicrob. 2006;5:5.
  7. Portillo A, Vila R, Freixa B, et al. Antifungal activity of Paraguayan plants used in traditional medicine. J Ethnopharmacol. 2001;76(1):93-98.
  8. Muller K, Sellmer A, Wiegrebe W. Potential antipsoriatic agents: lapacho compounds as potent inhibitors of HaCaT cell growth. J Nat Prod. 1999;62(8):1134-1136.
  9. Bohler T, Nolting J, Gurragchaa P, et al. Tabebuia avellanedae extracts inhibit IL-2-independent T-lymphocyte activation and proliferation.Transpl Immunol. 2008;18(4):319-323.
  10. Son DJ, Lim Y, Park YH, et al. Inhibitory effects of Tabebuia impetiginosa inner bark extract on platelet aggregation and vascular smooth muscle cell proliferation through suppressions of arachidonic acid liberation and ERK1/2 MAPK activation. J Ethnopharmacol. 2006;108(1):148-151.
  11. Lee JH, Cheong J, Park YM, Choi YH. Down-regulation of cyclooxygenase-2 and telomerase activity by beta-lapachone in human prostate carcinoma cells. Pharmacol Res. 2005;51(6):553-560.
  12. Lee JI, Choi DY, Chung HS, et al. beta-lapachone induces growth inhibition and apoptosis in bladder cancer cells by modulation of Bcl-2 family and activation of caspases. Exp Oncol. 2006;28(1):30-35.
  13. Kung HN, Chien CL, Chau GY, et al. Involvement of NO/cGMP signaling in the apoptotic and anti-angiogenic effects of beta-lapachone on endothelial cells in vitro. J Cell Physiol. 2007;211(2):522-532.
  14. Kim SO, Kwon JI, Jeong YK, et al. Induction of Egr-1 is associated with anti-metastatic and anti-invasive ability of beta-lapachone in human hepatocarcinoma cells. Biosci Biotechnol Biochem. 2007;71(9):2169-2176.
  15. Block JB, Serpick AA, Miller W, Wiernik PH. Early clinical studies with lapachol (NSC-11905). Cancer Chemother Rep 2. 1974;4(4):27-28.
  16. Foster S. Tyler's Honest Herbal: A Sensible Guide to the Use of Herbs and Related Remedies. New York: Haworth Herbal Press; 1999.
  17. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy (OR): Eclectic Med Publications; 1998.
  18. Woo HJ, Park KY, Rhu CH, et al. Beta-lapachone, a quinone isolated from Tabebuia avellanedae, induces apoptosis in HepG2 hepatoma cell line through induction of Bax and activation of caspase. J Med Food. 2006;9(2):161-168.
  19. Byeon SE, Chung JY, Lee YG, et al. In vitro and in vivo anti-inflammatory effects of taheebo, a water extract from the inner bark of Tabebuia avellanedae. J Ethnopharmacol. 2008 Sep 2;119(1):145-52.
  20. Freitas AE, Budni J, Lobato KR, et al. Antidepressant-like action of the ethanolic extract from Tabebuia avellanedae in mice: evidence for the involvement of the monoaminergic system. Prog Neuropsychopharmacol Biol Psychiatry. 2010 Mar 17;34(2):335-43.
  21. Mukherjee B, Telang N, Wong GY. 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.
  22. de Cássia da Silveira E Sá R, de Oliveira Guerra M. Reproductive toxicity of lapachol in adult male Wistar rats submitted to short-term treatment. Phytother Res. 2007 Jul;21(7):658-62.
  23. Maistro EL, Fernandes DM, Pereira FM, Andrade SF. Lapachol induces clastogenic effects in rats. Planta Med. 2010 Jun;76(9):858-62.
  24. Xu J, Wagoner G, Douglas JC, Drew PD. β-Lapachone ameliorization of experimental autoimmune encephalomyelitis. J Neuroimmunol. 2013 Jan 15;254(1-2):46-54.
  25. Sunassee SN, Veale CG, Shunmoogam-Gounden N, et al. Cytotoxicity of lapachol, β-lapachone and related synthetic 1,4-naphthoquinones against oesophageal cancer cells.Eur J Med Chem. 2013 Apr;62:98-110.

Consumer Information

How It Works

Bottom Line: Pau D'arco has antibacterial and anticancer activities in laboratory studies, but these effects have not been shown in humans.

Pau D'arco, a tree native to South America, has been used in traditional medicine for a wide range of ailments. In laboratory studies, compounds extracted from Pau d'arco showed antibacterial, antifungal, anti-inflammatory, antidepressant, and anticancer properties. However, the safety and effectiveness of these compounds has not been tested in humans.

Purported Uses
  • To treat cancer
    A small study done on 21 cancer patients did not show any benefits of Pau D'arco.
  • To treat infections
    Laboratory studies showed that Pau D'arco has antibacterial and antifungal activities. It has not been tested in humans.
Patient Warnings
  • Some compounds found in Pau D'arco may have toxic effects.
Side Effects
  • Nausea
  • Vomiting
  • Dizziness
  • Anemia
  • Increased risk of bleeding
  • Discoloration of urine
  • Short term administration of Lapachol caused reproductive toxicity (significant reduction in the weight of the seminal vesicle) in adult male rats.
  • Oral administration of Lapachol resulted in chromosomal aberrations in rats.
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