The folks at Science-Based Medicine and Respectful Insolence have been pointing out for a while that the Huffington Post has become a mainstream media champion for unreliable alternative medical information. And fortunately for us, HuffPo isn’t ignoring the veterinary side of alternative medical propaganda. Dr. Richard Palmquist, President-Elect of the American Holistic Veterinary Medical Association (AHVMA), of which I recently ran afoul, contributes a column to HuffPo. His latest commentary is instructive in that it illustrates the free mixing of reasonable ideas and science with nonsense made up out of thin air, in order to make the two indistinguishable and paint opinion and unsupported belief with a patina of scientific respectability.

In Veterinarians Team with Mother Nature for Better Results, Dr. Palmquist begins with the tried and true appeal-to-nature fallacy:

Scientists are pretty smart, but give them a bucket of carbon, oxygen, hydrogen, sulfur, iron, nitrogen and a few other miscellaneous things and see how many tomatoes they can make from scratch.

Nature is smarter.

Of course, scientists can’t whip up rattlesnake venom, syphilis, hookworms, tsunamis, or many other natural phenomena from scratch either. What’s the point here? If it is that what nature comes up with is better than what humans can make, I think that’s childish reasoning. “Nature” is just our personification of impersonal and undirected processes that have resulted in everything that exists, including human beings and their inventions, and it cares not a whit for our happiness and well-being. We like to say nature makes the good stuff, like puppies and strawberries, and we make all the toxic waste, but the reality is that nature made polio and we made the vaccine, so sometimes we are the good guys..

Dr. Palmquist then proceeds to make the true and quite reasonable observation that many useful medicines come from plants. Of course, this requires humans to analyze, purify, process, mimic, and test all sorts of compounds to find a few useful ones, none of which come without drawbacks, so how natural or inherently benign all of this is open to question. In any case, he inserts another assumption into this otherwise reasonable point, namely that the plants that contain substances useful as medicines were identified as medicinal and used to heal diseases by folk traditions a long time before science stumbled across their usefulness.

I am not aware of any evidence to support this notion, though it is commonly put forward by advocates of herbal remedies and traditional folk medicine in general. It may be true, but there are several reasons why I am doubtful of this assertion and would like something more than herbalists’ word for it. Prominent among them is confirmation bias, the tendency to focus on those examples which support one’s position and ignore those that don’t.

1. Many pharmaceuticals derived from plants, animals, fungi and other natural sources are discovered for reasons not related to folk medicine use. Someone notices that mold in a petri dish inhibits bacterial growth near it, and penicillin is discovered. Scientists work out that blowfish toxin paralyzes muscles and the chemical turns out to be useful in surgery. There are lots of reasons why a particular compound is pursued as a possible medicine apart from its traditional folk medicine use.

2. Most of the folk remedies one can find in historical documents turn out not to work reliably when tested, so Dr. Palmquist is guilty of counting the “hits” and ignoring the “misses.” If folk tradition were a reliable guide to which plants have medicinal value and which don’t, then the plants used in folk traditions should turn out to produce useful medicine more often and more reliably than those not so used. I have seen no evidence investigating this questions, so while it is possible it is by no means safe to assume it is true.

3. Almost every plant has been identified by some culture at some place and time to have medicinal properties. And when these properties are described, the plants are often said to treat a huge number of unrelated symptoms and diseases. When a plant turns out to contain a substance useful for a particular medical problem, one can almost certainly find a reference somewhere to that plant being used for that problem. This ignores the fact that the vast majority of claims made in traditional use of plants are either untested or shown to be untrue, so again Dr. Palmquist is cherry picking the examples where someone somewhere guessed right and ignoring all the wrong guesses.

4. As the post properly points out, getting medicines from plants almost always requires isolating, purifying, and altering chemicals to get better efficacy and fewer side effects. Most compounds investigated as possible drugs fail because they do more harm than good, or no good at all, and those that do succeed are often quite different from what one gets when eating plant parts directly. But Dr. Palmquist persists in putting forward the notion that a mixture of chemicals found in nature is likely to be safer and more effective than isolated and processed compounds. The evidence of medical history is soundly against this idea.

Certainly, it is true that combinations of medications are often more effective than single medications in managing complex diseases. But these are combinations of individual agents that are well-studied and understood and that have demonstrable benefit alone as well as in combination. And the sad reality is that combinations of drugs often leads to drug interactions which can be harmful. Dr Palmquist can say that Vitamin E is synergistic with NSAIDs for cancer therapy, but it is also true that Vitamin C diminishes the effect of some cancer treatments, so he is again picking examples that support his point and ignoring those that do not.

So why should we believe that the combination of chemicals found in a plant was somehow designed by nature to be ideal for treating a disease? Why should we think the combinations of plant ingredients created by folk medical traditions, arrived at either by uncontrolled trial and error or often fantastical theories based on religion, astrology, sympathetic magic, and so on, should be safer and more effective than medicines tested scientifically? Especially given the far greater success of medical science at treating diseases than any previous system has achieved in human history. And how do we explain the contamination of herbal remedies with toxins or even prescription drugs?[see references below] Dr. Palmquist answers none of these concerns but simply blithely assumes that what is natural and traditional is likely to be better than what is manmade and science-based.

There is no doubt nature, which after all describes everything that exists unless one arbitrarily chooses to exclude humans and their activities, holds many medical therapies yet to be discovered. But there is significant doubt that these therapies have already been identified in their safest and most effective form by herbalists and other folk medicine traditions. The reality is that science has taken not only the theories of these traditions but many other ideas they never conceived and created a wealth of medicines undreamt of before the age of scientific medicine. So to say nature knows best is at least naïve and at most an ideological even religious statement of faith rather than a scientific statement of fact. Dr. Palmquist is entitled to his faith like the rest of us, of course, but it should be clearly identified as such, not put forward by HuffPo as if it were established, accepted science.

References 

Herbal Preparations, Including Ayurvedic and Traditional Chinese Medicine (TCM) Herbs:

Aliye Uc, MD, Warren P. Bishop, MD, and Kathleen D. Sanders, MD, Camphor hepatoxicity. South Med J 93(6):596-598, 2000,

Angkana R, Lurslurcharchai L, Halm E, Xiu-Min L, Leventhal H, et al. Use of herbal remedies and adherence to inhaled corticosteroids among inner-city asthmatic patients. Annal Allerg Asthma Immunol 2010:104(2);132-138.

Berberine. Inbaraj JJ, Kukielczak BM, Bilski P, Sandvik SL, Chignell CF.   Photochemistry and photocytotoxicity of alkaloids from Goldenseal (Hydrastis canadensis L.) Chem Res Toxicol 2001 Nov;14(11):1529-34

Booth JN 3rd, McGwin G. The association between self-reported cataracts and St. John’s Wort. Curr Eye Res. 2009 Oct;34(10):863-6.

Burkhard PR, Burkhardt K, Haenggeli CA, Landis T. Plant-induced seizures: reappearance of an old problem. J Neurol 1999 Aug;246(8):667-70

Coon JT, Ernst E. Panax ginseng: A Systematic Review of Adverse Effects and Drug Interactions. Drug Saf 2002;25(5):323-44 Drug Saf 2002;25(5):323-44

Cupp MJ  Herbal remedies: adverse effects and drug interactions. Am Fam Physician 1999 Mar 1;59(5):1239-45

Debelle FD, Vanherweghem JL, Nortier JL. Aristolochic acid nephropathy: a worldwide problem. Kidney Int. 2008 Jul;74(2):158-69. Epub 2008 Apr 16.

Emery DP, Corban JG  Camphor toxicity. J Paediatr Child Health 1999 Feb;35(1):105-6

Ernst E Adverse effects of herbal drugs in dermatology. Br J Dermatol 2000 Nov;143(5):923-

Fugh-Berman A Herb-drug interactions. Lancet 2000 Jan 8;355(9198):134-8

Huang WF, Wen KC, Hsiao ML. Adulteration by synthetic therapeutic substances of traditional Chinese medicines in Taiwan. J Clin Pharmacol. 1997 Apr;37(4):344-50

Kutz GD. Herbal dietary supplements: Examples of Deceptive or questionable marketing practices and potentially dangerous advice. General Accounting Office. May 26, 2010.

Lai MN, Lai JN, Chen PC, Tseng WL, Chen YY, Hwang JS, Wang JD. Increased risks of chronic kidney disease associated with prescribed Chinese herbal products suspected to contain aristolochic acid. Nephrology (Carlton). 2009 Apr;14(2):227-34.

Lawrence JD.  Potentiation of warfarin by dong quai. Page RL 2nd, Pharmacotherapy 1999 Jul;19(7):870-6

Means C.  Selected herbal hazards. Vet Clin North Am Small Anim Pract 2002 Mar;32(2):367-82

Nizsly N, Grizlak B, Zimmerman M, Wallace R. Dietary Supplement Polypharmacy: An Unrecognized Public Health Problem? eCAM 2010 7(1):107-113

Norred CL, Finlayson CA Hemorrhage after the preoperative use of complementary and alternative medicines. AANA J 2000 Jun;68(3):217-20

O’Connor A, Horsley CA. Yates, KM “Herbal Ecstasy”: a case series of adverse reactions.  N Z Med J 2000 Jul 28;113(1114):315-7

Pittler MH. Ernst, E Risks associated with herbal medicinal products. Wien Med Wochenschr 2002;152(7-8):183-9

Poppenga RH. Risks associated with the use of herbs and other dietary supplements. Vet Clin North Am Equine Pract. 2001 Dec;17(3):455-77, vi-vii

Pies R  Adverse neuropsychiatric reactions to herbal and over-the-counter “antidepressants”. J Clin Psychiatry 2000 Nov;61(11):815-20

Prakash S, Hernandez GT, Dujaili I, Bhalla V. Lead poisoning from an Ayurvedic herbal medicine in a patient with chronic kidney disease. Nat Rev Nephrol. 2009 May;5(5):297-300.

Raman P, Patino LC, Nair MG. Evaluation of metal and microbial contamination in botanical supplements. J Agric Food Chem. 2004 Dec 29;52(26):7822-7

Ruschitzka F, Meier PJ, Turina M, Luscher TF, Noll G  Acute heart transplant rejection due to Saint John’s wort. Lancet 2000 Feb 12;355(9203):548-9

Saper RB, Phillips RS, Sehgal A, Khouri N, Davis RB, Paquin J, Thuppil V, Kales SN. Lead, mercury, and arsenic in US- and Indian-manufactured Ayurvedic medicines sold via the Internet. JAMA. 2008 Aug 27;300(8):915-23.

Shad JA, Chinn CG, Brann OS Acute hepatitis after ingestion of herbs. South Med J 1999 Nov;92(11):1095-7

Smolinske SC J Am Med Womens Assoc 1999 Fall;54(4):191-2 Dietary supplement-drug interactions.

Tachjian A, Maria V, Jahangir A. Use of herbal products and potential interactions in patients with cardiovascular disease. J. Am. Coll. Cardiol. 2010 55: A32

Yang HY, Wang JD, Lo TC, Chen PC. Increased mortality risk for cancers of the kidney and other urinary organs among Chinese herbalists. J Epidemiol. 2009;19(1):17-23. Epub 2009 Jan 22.

Zhang SY, Robertson D. A study of tea tree oil ototoxicity. Audiol Neurootol 2000 Mar-Apr;5(2):64-8

Kidney failure from aristolochia in TCM herbals preparations.

Lead, mercury and arsenic in herbal preparations.

Lead in TCM preparations.

Lead in ayurvedic preparations.

Lead in herbal preparations.

Tea Tree Oil Can be toxic to cats.

Toxic metals in Brazilian herbal preparations.

Contamination of herbal products with undisclosed pharmaceuticals.

Widespread contamination of supplements with undisclosed toxins and parmaceuticals

Harriett Hall, The SkepDoc from whom I cribbed my moniker, recently wrote on the science-Based Medicine blog about the new Mayo Clinic guide to home remedies, which sounds like a sensible guide to appropriate kinds of self-treatment for minor medical problems. Despite the accusations of the fringes of the alternative medicine movement, that doctors are driven by greed and love to provide unnecessary treatment for minor ailments, the reality is that doctors prefer to treat the truly ill, not those with problems that will resolve themselves. People who go to the doctor with self-limiting viral infections for which there is no effective treatment are accomplishing nothing other than sharing their virus with their healthcare providers, so if they could treat their own symptoms at home I’m sure their doctors would be thrilled. And I frequently discuss with my clients both indications that a pet needs to come in to see me and indications that they don’t and can be managed by their owners at home.

The thing is, most mild ailments do get better all by themselves. This is one of the reasons nonsense therapies often seem to work. If you have a common cold, a headache, an upset tummy from too much spicy chili, and so on, you are likely to feel better pretty soon no matter what you do. So home remedies are fine if they make you feel better (by placebo or real effects), or if they just give you something to do while waiting to get better.

The key, though, is that while it isn’t so important if home remedies are effective, since they are only appropriate for mild, self-limiting illnesses, it is critical that they be benign. Any remedy that does harm for a mild disease that’s going to get better on its own is automatically doing more harm than good, unlike a medication which may cause harm that is worth tolerating in order to treat a more serious disease.

I had a case the other day which exemplifies the problem with home remedies: ineffective and potentially harmful treatments applied with no understanding of medicine or even common sense. An otherwise healthy cat had developed some patches of hair loss which the owner self-diagnosed as ringworm (a fungal infection). The owner attempted to treat this with a commonly recommended remedy of vinegar and grapefruit seed extract. There is no good quality evidence this mixture is effective even if ringworm is present, though some laboratory research suggests grapefruit seed extract may have little effect on this particular kind of fungus, and like many “natural” remedies may have contaminates that can present a health hazard.

The cat developed vomiting, diarrhea, and a loss of appetite after licking itself where the remedy was applied. The owner attempted to treat this with activated charcoal and probiotics. I’ve written about probiotics in general (as well as about specific uses and studies and some of the more egregiously fraudulent marketing of them), and there is some plausibility to the idea they may be useful for some kinds of diarrhea, though this is not at all proven in dogs and cats. And activated charcoal is an appropriate agent to give animals suspected of ingesting poison, since it can reduce absorption of the toxins. However, a cardinal rule of treating toxin exposures is never give oral medications, especially charcoal, to an animal that is vomiting. Not only will these likely incite more vomiting, but there is a great risk of aspirating the charcoal into the lungs, which can cause a serious pneumonia. This was clearly a case where a home remedy was not indicated.

The client brought the pet in and was given some suggestions about medications and feeding, with the main suggestion being to let the cat alone. The hardest thing for any pet owner to do when their companion is sick is nothing, even when that’s the best thing to do. Like many people who feel they need little or no veterinary advice to treat their own pets, the owner had a stock of left over medications previously prescribed for other pets which the person was eager to use. And in the absence of being told to use them, the client was eager to apply home remedies rather than simply give the cat time to recover naturally.

The next day, the cat was no longer vomiting but didn’t want to eat and still had soft stools. In addition to giving the cat a variety of foods, including some clearly inappropriate for a patient with a gastrointestinal problem, such as egg yolks, the owner then attempted to treat the diarrhea by giving the cat two enemas, one with aloe vera and another with flax seed oil. Apart from the lack of any evidence to suggest either of these substances have benefit for GI upset, and the utter ridiculousness of the colon cleansing and intestinal toxicity ideas, the notion of treating diarrhea by giving enemas is every bit as stupid as it sounds. Such treatment is not only going to further aggravate the original problem but can potentially cause serious injury, especially performed by someone without proper training in an inadequately controlled environment.

The clearest evidence of this person’s complete lack of not only medical knowledge but even common sense was when they seemed both worried and puzzled by the fact that the cat was reluctant to be picked up or touched near the hind end by the owner!

Home remedies are perfectly appropriate for mild, self-limiting conditions, as long as the remedies themselves do no harm. But as this case illustrates, determining when it makes sense to use such remedies, and what kinds of treatments are appropriate for what conditions, is not apparently as straightforward as proponents of treating your own pets at home would have you believe. No doubt most pet owners are sensible enough, and have enough understanding of the limitations in their own knowledge and skill, to be trusted to recognize when their pets need professional care and when they can try using simple home remedies themselves. However, in my years of practicing I have seen many, many cases of unbelievably inappropriate treatments and horrible neglect due to a complete lack of any understanding by owners of what is mild and what is serious disease and what remedies they can reasonably apply on their own, so I believe we must be very cautious when telling pet owners they don’t necessarily need to seek veterinary care when their pets are sick.

The most important part of any guide to home remedies should not be the treatments themselves, those these should of course at least be safe. The most important thing such a guide should emphasize is that owners must recognize the limitations of their own medical knowledge and understanding and know when to call their vet. Ultimately, home remedies may or may not effectively treat symptoms, but they are only appropriate if they do no harm and if they are used for conditions that are going to get better on their own regardless of whether we do anything at all.