Archive for February 23rd, 2010

Medicinal Herbs: Not to Be Taken (or Given) Lightly

February 23, 2010

As a small animal internist, the majority of my patients are referred by their family veterinarians.  By the time I first examine them, they are usually receiving a laundry list of conventional medications (antibiotics, nonsteroidal antiinflammatories, etc.) and/or complementary medications (herbs, homeopathic remedies).   I’ve always scrutinized the conventional medications on the list because their potential side effects and the ways they might impact my diagnostic and therapeutic planning.  I’ve tended to pay far less attention to the complementary medications because of my impression that these medicinals are unlikely to cause significant harm or interact unfavorably with other things I might prescribe. Well, there will be no more of this “ignorant bliss” for me! Not after reading, “A Review of the Potential Forensic Significance of Traditional Herbal Medicines” from the Journal of Forensic Science (January, 2010).  The author, Roger Byard, M.D. undertook a review of herbal medicines based on their increasing popularity (there has been a steady 10% increase in spending on botanical remedies in the United States) and the fact that access to such products is largely unrestricted- they can be purchased without prescription. Keep in mind that herbs are manufactured and sold without any FDA approval process.

Here are some of Dr. Byard’s comments and findings:

-An analysis of 251 Asian herbal products from stores in California identified arsenic in 36, mercury in 35, and lead in 24. There have been reports of lead poisoning and mercury poisoning in people caused by such contamination.
-Less expensive herbs are sometimes intentionally used to replace those that are more costly. A case is referenced in which an herb designed to promote weight loss was replaced with another. The unfortunate result for the patient was kidney failure.
-Accidental substitution can occur if plants are incorrectly identified or if the name is misinterpreted. Apparently, some traditional herbal preparations have multiple names. To make matters even more confusing, some herbal preparations that are different from one another go by the same name.
– Failure to process fresh herbs correctly can have serious consequences. Processing is designed to clean and preserve the desired material while removing or reducing any unwanted toxic components. The example provided was aconite root, a plant that must be soaked in water and boiled to reduce toxicity. Failure to do this can result in heart rhythm abnormalities and/or heart failure.
-Some herb manufacturers purposefully adulterate their products with drugs presumably to increase their efficacy. Yet no mention of this is made on the packaging. Examples of hidden products found in herbal preparations have included conventional medications to treat pain, inflammation, seizures, heart failure, and asthma.
-Herbal medicines can interact with conventional drugs and other herbs to cause undesirable side effects. For example, St. John’s Wort can decrease the blood level of some medications by impacting how they are metabolized within the liver.
-The American Society of Anesthesiologists has recommended discontinuation of herbal medicines at least two weeks prior to surgery because of their potential for causing complications. Although only eight herbs were identified as being potentially dangerous, they accounted for 50% of all single herb preparations of those sold within the United States. For example, Ginkgo has the potential to increase the risk of hemorrhage and Valerian can exacerbate the sedative effects of anesthetic agents.

Although Dr. Byard’s review is based on findings in human medicine, I have to believe that the general points he makes likely apply to veterinary medicine as well. His review has certainly served as a wake up call for me. If you use herbs, for your pets or yourself, perhaps this information will prompt you to think about things a bit differently as well. What is a practical approach for avoiding the potential pitfalls associated with herbal medications? I encourage you to consider doing the following:

  1. If you are giving herbs to your pet based on your own initiative, schedule an appointment with your vet to discuss and verify that what you are doing is reasonable and safe.
  2. Have a look at the blog I posted in July, 2009 ( called, “The Lowdown on Nutritional Supplements.” It will teach you how to use the ACCLAIM system to evaluate the quality of herbal products.
  3. Pick up a copy of the Physician’s Desk Reference (PDR) for Nonprescription Drugs, Dietary Supplements, and Herbs. It provides information about the indications, contraindications, and warnings for all commonly used herbs. This PDR is readily available via major online book vendors. I will certainly be using my own copy a whole lot more than ever before!

I hope I have not created fear or anxiety by presenting this information. Rather, my goal is to help you become the very best medical advocate possible. Now, like me, you know that herbal medications should not be taken (or given) lightly. If you provide herbs to your pet(s), I would love to hear from you. Please let me know which one(s) you are giving and whether you or your veterinarian initiated this treatment.

Best wishes to you and your four-legged family members for abundant good health.

Nancy Kay, DVM
Diplomate, American College of Veterinary Internal Medicine
Recipient, American Animal Hospital Association 2009 Animal Welfare and Humane Ethics Award
Recipient, 2009 Dog Writers Association of America Award for Best Blog
Recipient, 2009 Eukanuba Canine Health Award
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life

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Please visit to read excerpts from Speaking for Spot. There you will also find “Advocacy Aids”- helpful health forms you can download and use for your own dog, and a collection of published articles on advocating for your pet’s health. Speaking for Spot is available at, local bookstores, or your favorite online book seller. 


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