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Featuring Demian Dressler, DVM and Sue Ettinger, DVM, Dip. ACVIM (Oncology), authors of The Dog Cancer Survival Guide

Pau D’Arco for Dogs With Cancer: Be Careful Says Dr. Dressler

Updated: April 13th, 2021

In the last post, I focused on really looking at the source of the information you are receiving about your dog’s cancer.  Let’s get into some specific examples of questionable “intelligence” you may have received.

Some, claiming authority in the area of supplements for dog cancer, are pushing Pau D’Arco.  Be careful, everyone!

Let’s look at Pau D’Arco.  This is the common name for a tea, capsule, liquid extract, salve or tablet from  Tabebuia impetiginosa, a tree common in South America, especially Brazil. The bark is used for these medicinal preparations.

Pau D’Arco does have a lot of postive test-tube  (“in vitro”) effects on cancer cells.  Unfortunately, lots and lots of compounds kill cancer cells in test tubes.  The clinical trials in people (“in vivo”, or in living bodies) have been mixed, with the most well-designed one (“Early Clinical Studies With Lapachol”) yielding little benefit.

The American Cancer Society does not like Pau D’Arco for use in people due to safety concerns.  One could make the claim that they are just part of the “machine” trying to keep miracle cures suppressed to aid Big Pharma.

Whatever your belief is, and few people could deny the force of Big Pharma’s strategic influence, the concern over safety and effectiveness is well-founded at this point.

What is the evidence?

Well, lapachol, an active component Pau D’Arco, is toxic to developing embryos in pregnant lab animals.  It also messes up fertility of male lab rats. Okay, granted,  most chemotherapy agents have similar effects, so Pau D’Arco cannot be tossed out on this basis alone.  It should never be used in breeding animals, obviously.

At oral doses necessary for required concentrations around cancer cells, Pau D’Arco caused vomiting, blood clotting problems, and diarrhea.  Well, these are not good either, but one could also state these side effects are seen with chemo too, and that would be a valid point.  Of course, it is no-brainer to state that Pau D’Arco should never be used before surgery, during wound healing, in animals with blood clotting problems, or with tumors that could bleed.

Pau D’Arco has hydroquinone in it.  This is bad stuff.  Not only is it carcinogenic (irony of all ironies), but it is toxic to vital organs too.  Read all about it here.  Well, again, the same could be said of some of our common chemo drugs.

So what really makes Pau D’Arco dicey?  One thing that is quite bothersome is a lack of batch standardization.  Not only do the lapachol and other components vary from tree to tree, but sometimes they are actually absent.

On top of that, sometimes the the trees from which the bark is taken are from different Tabebuia species.  The tree appears to be getting more scarce due to it’s reputation, and we are getting herbal preparations containing the wrong bark.

Finally, chemo drugs are used under strict veterinary supervision. Pau D’Arco usually is not.  Both have real side effect concerns. Substances with these possible adverse health effects should not be used by a layperson without supervision.

There is no doubt that Pau D’Arco should be studied more or used as a template for new drugs, since the active compounds in the bark may have merit. However, since it contains some things that could, from time to time, pose real health hazards, and the batches vary in composition (does your dog’s batch have a lot of hydroquinone???), it is a gamble that I cannot take with dogs I care about.

Please be careful of what you read!

For more information on herbs or supplements for dogs with cancer, check out The Dog Cancer Survival Guide.

Best to all,

Dr D

Leave a Comment

  1. E Conner on January 23, 2021 at 5:41 am

    Dr. Dressler,
    What is your opinion of treating adenocarcinoma with palladia ? It has made the tumors shrink considerably. Is there any support for white blood cell production during this treatment ? Thanks for the good info and feedback

  2. D. Womack on September 16, 2018 at 5:59 pm

    The American Cancer Society doesn’t like anything for cancer treatment except chemo and radiation. To better rephrase that, they don’t like anything they can’t make money off of. Pau d’ Arco can’t be patented and is all natural. The Argentina Government gives it to cancer patients for free because of it has such good results.

  3. Wide Awakening on June 20, 2014 at 8:15 am

    Very short sighted article. They pulled a single compound out of Pau d’arco, Lapachol, and did studies on that single compound. Why? Because it’s the ONLY compound they could successfully patent. When the whole inner bark is used with ALL the constituents included, as it would be in nature, all those concerns dissipate (with the exception of its blood thinning capacities).

    I have used Pau d’arco for decades. My cats as long as they have been alive, which is since +/- 2002. We are all incredibly healthy.

  4. JR on January 21, 2013 at 2:22 pm

    Dr. D – your hydroquinone information is extreme. Please consider revisiting the issue of overload of hydroquinone that is naturally-occurring..

    Miss Private – Very sorry your dog had kidney failure. Please try not to post cause-effect without any background history, dosage used, brand…

    • Dr. Demian Dressler on January 23, 2013 at 11:37 am

      Dear JR,
      please submit any pertinent information that we should be considering with scientific backing and I would be happy to assess it.
      Dr D

  5. Miss Private on September 14, 2012 at 9:24 am

    I gave my Dog Pau ‘d Arco and it gave her kidney failure. I wish I read your article before I gave it too my Dog.Please people, do not give this herb to your animals.

  6. Kristen on March 18, 2012 at 6:12 am

    I used it topically on a tumor on my dog. The tumor dissappeared and has not returned!

  7. Lynne on November 16, 2009 at 12:00 pm

    One of our dogs, Oly, has osteosarcoma. We had surgery for the removal of the tumor and are treating with chemotherapy, and trying to treat with a combination of herbs and vitamins, including Aloha Medicinals’ K-9 Immunity. Two weeks ago Oly was also diagnosed with valley fever after a scarey elevation in his temperature following chemotherapy. Now he is on fluconazole to treat the valley fever, as well. The K-9 Immunity seems to make him feel poorly and we’re wondering if that’s because fluconazole is an anti-fungal and K-9 Immunity is a mushroom-based product. The folks at Aloha Medicinals have not been presented with this problem before and did not know the answer. Thank you for your time.

    • Dr. Dressler on November 29, 2009 at 9:30 pm

      although I cannot make a direct link between the activity of fluconazole, if a given dog has an intolerance to a given supplement, it should be discontinued. Some people can’t do penicillin, or shellfish, or get the idea.
      Dr D

  8. Clou on October 16, 2009 at 8:42 am

    I have read alot on natural healing and according to the Homeopathic doctors and Naturopathic doctors, they use Pau D’Arco in treating candida albicans which is yeast overgrowth. According to this field of study they feel there is a definite link of fungi in the body to contributing to many diseases including cancer. I have used it as a tea in treating the yeast infections and it works very well.

    • Dr. Dressler on October 17, 2009 at 5:17 pm

      Hi Clou,
      Indeed, Pau D’Arco is used with at times good benefit. And the antimicrobial effects are very nice indeed. The problem is the batch standardization and lack of control over what we are doing, but that is another really interesting point about the medicinal….thanks for your input!
      Dr D

  9. Kammee on October 16, 2009 at 8:22 am

    Cr Dressler,
    How do you feel about doing a pet scan vs. MRI thermography and cat scan. WHat are the bennifits of eact and are there any down falls. I know it is hard to find vets that do thermography and pet scans but I have found one. I am curious is it is worth the extra $ for mass cell. My concern for my dog is that it has spread and I want to find out how much and where. My dogs fine needle asperiates were clear in his liver and pancreas but My gut is telling me he is getting worse. Chemo is not an option for him since I do not believe in it. Any help would be great, Thanks Kammee

  10. Spirit Jerry G. Dawg on October 13, 2009 at 5:43 am

    Thanks Dr. D, as always we really appreciate your research and great information about herbal supplements. P’au De Arco has been mentioned in our Tripawd forums before, and used by some Tripawd pawrents on their dogs. We’ll be sure to link to this post wherever it’s mentioned from here on out.

    You’re pawesome, keep it up!

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