Herbal (botanical) medicine involves the practice of prescribing plant products, or products derived directly from plants, for the treatment of disease. Herbal medicine has survived since prehistoric times, in part because, until recently, there were no effective alternatives. Some plants do contain biologically active ingredients, and some pharmaceuticals in widespread use today are identical to, or derivatives of, bioactive constituents of historic folk remedies. Indeed, herbal and botanical sources purportedly form the origin of as much as 30% of all modern pharmaceuticals.
Evidential support concerning use of plant products in veterinary patients is scarce and ranges from effective and safe to ineffective and risky. However, the methodologic quality of primary studies on herbal medicines for many species is generally poor. Trials usually lack firm endpoints, and periods of observation are usually short; the clinical relevance of the observed effects is not always clear. In addition, data that directly compare herbal remedies with well-established pharmaceutical products are often not available. However, as the database on herbs continues to grow, veterinarians seeking to prescribe natural, plant-based compounds should always review the latest scientific literature for information on the compound or product of interest.
Making a rational decision about an herbal product requires knowledge of its active ingredients, its safety and adverse effects, and whether the herb has been shown to be as good as or better than pharmaceutical products available for the same purpose. This information is incomplete or unavailable for most herbal products. In addition, there are no standards or quality control testing of the products regularly recommended for animals. Risk versus benefit questions must be considered for products with unclear constituents and unknown or undisclosed (ie, proprietary) ingredients.
When treating pain, for example, veterinarians seeking to incorporate botanical treatments should consider the type of discomfort being treated (eg, inflammation, myalgia, mental/emotional/physical distress), along with patients' comorbidities, intolerances, and current medications. Adding herbs to the mix has the potential to affect plasma concentrations of coadministered pharmaceuticals.
Common Botanical Products in Veterinary Medicine
Name | Suggested Attributes | Suggested Mechanisms of Action | Reported Adverse Effects | Notes, Drug-Herb Interactions |
|---|---|---|---|---|
Boswellia (Boswellia serrata) | Analgesic Anti-inflammatory Anticancer | Inhibits 5-lipoxygenase and cyclo-oxygenase-1 Inhibits nuclear transcription factor kappa B (NF-kappa B) signaling, thereby decreasing production of tumor necrosis factor alpha (TNF-alpha) Cytotoxic Radioenhancing Improves cognitive function Lowers insulin resistance | Typically well tolerated; occasional GI upset | Unknown clinical significance regarding anion transporter OATP1B3, multidrug resistant protein MRP2, and P-glycoprotein May inhibit platelet aggregation and thereby increase risk of bleeding |
Turmeric (Curcuma longa) | Analgesic Anti-inflammatory Anticancer Antiemetic | Decreases TNF-alpha concentration Antiproliferative Inhibits matrix metalloproteinase Radioenhancing, chemosensitizing | Diarrhea, flatulence, and/or bloating with high doses May lead to headache and nausea | May increase risk of bleeding when combined with NSAIDs Unknown clinical significance of interactions with chemotherapeutic drugs |
Ginger (Zingiber officinale) | Analgesic Anti-inflammatory Anticancer Hypoglycemic Antiemetic Regulates GI motility Anti-infective for GI tract | Stimulates flow of saliva, bile, and gastric secretions Competitive antagonist of serotonin 5-HT3 receptors Inhibits thromboxane formation and platelet aggregation Stimulates mucosal cells to secrete interferon-beta to combat viral infection Reduces tumor growth by damaging microtubules and inducing mitotic arrest Inhibits angiogenic cytokines, vascular endothelial growth factor, and interleukin-beta in cell cultures Increases levels of circulating antioxidant and phase II enzymes Reduces lipid peroxidation levels | Abdominal discomfort, diarrhea, gastric irritation, and mucosal irritation of the oropharynx are possible. | May increase risk of bleeding when combined with NSAIDs Can cause additive reductions in blood glucose when co-administered with other glucose-lowering substances. May lead to decreased blood concentrations of cyclosporine |
Devil's claw (Harpagophytum procumbens) | Analgesic Anti-inflammatory Antiosteoporotic Antioxidant Appetite suppressing | Decreases inflammatory cytokine production such as TNF-alpha Inhibits pro-inflammatory gene expression | GI bleeding, acute pancreatitis, gastric discomfort or ulcers | May affect blood levels of substances metabolized by cytochrome P450 enzymes due to its inhibition of several families of these enzymes. May impact drug transport mediated by P-glycoprotein. |
Cayenne or capsaicin (Capsicum frutescens) | Analgesic Circulatory support | Depletes substance P from C-fiber polymodal nociceptors. Activates transient receptor potential vanilloid subfamily member 1 (TRPV1). Releases calcitonin gene-related peptide (CGRP) to cause coronary vasodilation. | GI irritation with oral administration | Interacts with cytochrome P450 (CYP) 3A and P-glycoprotein (P-gp) substrates, leading to altered absorption and metabolism of co-administered medications. Drugs affected by capsaicin include ACE inhibitors, antihypertensive agents, antiplatelet drugs, immunosuppressants such as cyclosporine, and theophylline. |
Peppermint (Mentha piperita L.) | Analgesic for aches Alleviates digestive discomfort / antispasmodic Anti-inflammatory Anticancer Hypoglycemic/antidiabetic Antifungal Antibacterial Antifibrotic Antioxidant Anti-infective for GI tract | Diminishes calcium influx, thereby regulating calcium channel–dependent activities in GI tract smooth muscle Menthol reduces lipid peroxidation, oxidative stress, and inflammation in colitis animal model | Mild GI upset, nausea, vomiting with oral administration Dermatitis with topical administration | May increase risk of bleeding Unknown clinical significance of interactions with chemotherapeutic drugs |
Lavender (Lavandula angustifolia) | Anxiolytic Analgesic Anti-inflammatory Antioxidant Antimicrobial Anticonvulsant Neuroprotective Anti-infective for GI tract | Anti-inflammatory and analgesic effects are attributed to the terpene 1,8-cineole; linalool and linalyl acetate relax vasculature and counter anxiety | Nausea, confusion, eructation from oral administration Possible dermatitis and photosensitivity with topical administration | Additive effects with sedating medications are possible |
Kava (Piper methysticum) | Anticonvulsant Local anesthetic Skeletal muscle relaxant | Kavapyrones act on CNS to induce skeletal muscle relaxation | Hepatotoxicity Headache Urticaria Skin irritation Ataxia Altered mental status | Additive effects when co-administered with CNS depressants |
St John's wort (Hypericum perforatum) | Antidepressant Neuroprotective Analgesic for neuropathic pain | Hyperforin and hypericin may alleviate neuropathic pain and offer neuroprotective effects Inhibit neuronal uptake of serotonin, norepinephrine, and dopamine | Photosensitivity Increased prothrombin time GI upset Dry mouth Headache Nausea Neuropathy | Commonly causes herb-drug interactions Can lead to serotonin syndrome when combined with selective serotonin reuptake inhibitor(s) |
Reishi mushroom (Ganoderma lucidum) | Immunomodulatory Renoprotective Anti-inflammatory Hepatoprotective Anticancer | Beta glucans, polysaccharides provide antitumor and immunostimulatory activities Triterpene compounds may inhibit invasiveness of tumors by reducing expression of matrix metalloproteinases Additional anticancer possible | Nausea Insomnia | May increase risk of bleeding when given with anticoagulants and antiplatelet substances Can counter immunosuppressant drug activity by enhancing immune responses May counteract chemotherapeutic agents that rely on free radical formation by increasing plasma antioxidant activity. Inhibits cytochrome P450 enzyme activity so may affect intracellular concentrations of drugs metabolized by same CYP enzyme families. |
Milk thistle (Silybum marianum) | Treat various liver diseases Antioxidant Anticancer Reduce chemotherapy-induced hepatotoxicity and other adverse effects, including the severity of radiodermatitis (silymarin gel) | Silymarin may confer hepatoprotection by downregulating extracellular matrix proteins such as collagen May reduce liver carcinogenesis by inhibiting mast cells and matrix metalloprotein production Silibinin (a milk thistle flavonoid) demonstrates antioxidant and anti-inflammatory activity by inhibiting release of hydrogen peroxide and production of TNF-alpha Various anticancer effects such as arresting G1 and S phases of the cell cycle. | High doses of silibinin may increase bilirubin levels and liver enzymes | Effects on CYP 450 enzymes have unclear clinical significance |
Yunnan Baiyao (or Yunnan Paiyao) | Hemostatic Anti-inflammatory Antimicrobial Notoginseng, a major component, demonstrates the following activities when administered as a solo agent: Anticoagulant Antiplatelet Fibrinolytic | Although preparations vary across manufacturers and the ingredients are unknown (proprietary), it appears that some of the nanofiber components in Yunnan Baiyao may help activate blood clotting Notoginseng also reduces fibrinogen levels in the blood and protects endothelial function, among many other effects on platelets and immune cells | Estrogenic activity in notoginseng and ginsenosides may stimulate the growth of hormone-sensitive mammary cancer | May increase risk of bleeding when given with anticoagulant or antiplatelet medications May inhibit or induce cytochrome P450 enzymes and thereby alter the metabolism of substrate drugs of those enzymes |
Cannabidiol (Cannabis sativa) | Anti-inflammatory Anticonvulsant Analgesic Neuroprotective Antioxidant | Endocannabinoid modulator Inhibits pro-inflammatory pathways Interacts with multiple receptors and neurotransmitter pathways | Nausea Oversedation Inappetence Liver enzyme changes Possible reproductive system changes | Changes have been reported in co-administered anti-epileptic medications. Concern is growing about additional potential herb-drug interactions. |
The table Common Botanical Products in Veterinary Medicine includes a diverse group of examples comprise a diverse group of phytotherapeutics commonly considered to treat pain and/or inflammation. Caution is warranted when implementing such approaches because a full compilation of risks and benefits and therapeutic and toxic doses is largely unavailable.
A photograph of frankincense oleoresin gum from a Boswellia spp. The herb boswellia, also called “Indian frankincense,” harkens back to the ancient practice of ayurvedic medicine. Its main constituent, boswellic acid, confers anti-inflammatory and anti-arthritic effects by inhibiting 5-lipoxygenase and cyclooxygenase-1 production as well as NF-kappa B signaling, among other processes. Frankincense trees are almost extinct.
Courtesy of Dr. Narda Robinson.
Photograph of a fresh tumeric rhizome (Curcuma longa), a member of ginger family. Research on curcumin, the most intensively studied constituent of turmeric, suggests anti-inflammatory, immunomodulatory, neuroprotective, and antiproliferative actions; and clinical benefits. Reports of fraudulent and/or lead-contaminated ground turmeric spice preparations have increased in recent years.
Courtesy of Dr. Narda Robinson.
A ginger (Zingiber officinale) rhizome. One of the world’s oldest botanical remedies, ginger remains popular for its apparent digestive, antinausea, anti-inflammatory, and other healthful benefits. Despite its widespread usage, practitioners need to remain cognizant of ginger being included in the notorious “4 Gs” grouping (ginkgo, ginseng, ginger and garlic) - four plants with anticoagulant/antiplatelet effects that could complicate surgical procedures via unanticipated or excess bleeding.
Courtesy of Dr. Narda Robinson.
Whole dried reishi (Ganoderma lucidum) mushroom cap. One example of a range of Asian medical mushrooms sought for their purported immune-enhancing and anticancer effects. Its most prominent, pharmacologically active compounds include triterpenoids and polysaccharides (especially beta-d-glucans).
Courtesy of Dr. Narda Robinson.
Photograph of dried, sliced, reishi (Ganoderma lucidum) mushroom. This form allows for the preparation of broths and decoctions, ie, typical methods of extracting desired constituents.
Courtesy of Dr. Narda Robinson.
Photograph of milk thistle (Silybum marianum) seeds. Silymarin, the most prominent active constituent of milk thistle seeds, demonstrates hepatoprotective, antioxidant, and anticancer benefits. Although many veterinarians recommend milk thistle derivatives for patients with liver disease, few are familiar with the actual plant product.
Courtesy of Dr. Narda Robinson.
Photograph of Yunnan Baiyao capsules. This proprietary Chinese herbal formulation is sometimes prescribed to veterinary patients as an adjunctive approach to preventing or slowing hemorrhage, especially for conditions such as hemangiosarcoma in dogs, shock and other causes of bleeding. However, the mechanisms of action, its level of effectiveness, and whether it is safe are unknown, because insufficient research exists. Moreover, not all products labeled as Yunnan Baiyao contain the same ingredients, and many aspects remain undisclosed, untested, and unregulated.
Courtesy of Dr. Narda Robinson.
Photograph of capsules containing cannabidiol (CBD) and other hemp (Cannabis sativa) derivatives. Unregulated and often untested cannabis products sold for veterinary use may contain proprietary mixtures of cannabinoids, terpenes, and flavonoids. Although early studies suggest potential benefits for osteoarthritis and seizures in dogs, uncertainties persist regarding quality control, contents of proprietary remedies, herb-drug interactions, and the impact of long-term use.
Courtesy of Dr. Narda Robinson.
A photograph of frankincense oleoresin gum from a Boswellia spp. The herb boswellia, also called “Indian frankincense,” harkens back to the ancient practice of ayurvedic medicine. Its main constituent, boswellic acid, confers anti-inflammatory and anti-arthritic effects by inhibiting 5-lipoxygenase and cyclooxygenase-1 production as well as NF-kappa B signaling, among other processes. Frankincense trees are almost extinct.
Courtesy of Dr. Narda Robinson.
Photograph of a fresh tumeric rhizome (Curcuma longa), a member of ginger family. Research on curcumin, the most intensively studied constituent of turmeric, suggests anti-inflammatory, immunomodulatory, neuroprotective, and antiproliferative actions; and clinical benefits. Reports of fraudulent and/or lead-contaminated ground turmeric spice preparations have increased in recent years.
Courtesy of Dr. Narda Robinson.
A ginger (Zingiber officinale) rhizome. One of the world’s oldest botanical remedies, ginger remains popular for its apparent digestive, antinausea, anti-inflammatory, and other healthful benefits. Despite its widespread usage, practitioners need to remain cognizant of ginger being included in the notorious “4 Gs” grouping (ginkgo, ginseng, ginger and garlic) - four plants with anticoagulant/antiplatelet effects that could complicate surgical procedures via unanticipated or excess bleeding.
Courtesy of Dr. Narda Robinson.
Whole dried reishi (Ganoderma lucidum) mushroom cap. One example of a range of Asian medical mushrooms sought for their purported immune-enhancing and anticancer effects. Its most prominent, pharmacologically active compounds include triterpenoids and polysaccharides (especially beta-d-glucans).
Courtesy of Dr. Narda Robinson.
Photograph of dried, sliced, reishi (Ganoderma lucidum) mushroom. This form allows for the preparation of broths and decoctions, ie, typical methods of extracting desired constituents.
Courtesy of Dr. Narda Robinson.
Photograph of milk thistle (Silybum marianum) seeds. Silymarin, the most prominent active constituent of milk thistle seeds, demonstrates hepatoprotective, antioxidant, and anticancer benefits. Although many veterinarians recommend milk thistle derivatives for patients with liver disease, few are familiar with the actual plant product.
Courtesy of Dr. Narda Robinson.
Photograph of Yunnan Baiyao capsules. This proprietary Chinese herbal formulation is sometimes prescribed to veterinary patients as an adjunctive approach to preventing or slowing hemorrhage, especially for conditions such as hemangiosarcoma in dogs, shock and other causes of bleeding. However, the mechanisms of action, its level of effectiveness, and whether it is safe are unknown, because insufficient research exists. Moreover, not all products labeled as Yunnan Baiyao contain the same ingredients, and many aspects remain undisclosed, untested, and unregulated.
Courtesy of Dr. Narda Robinson.
Photograph of capsules containing cannabidiol (CBD) and other hemp (Cannabis sativa) derivatives. Unregulated and often untested cannabis products sold for veterinary use may contain proprietary mixtures of cannabinoids, terpenes, and flavonoids. Although early studies suggest potential benefits for osteoarthritis and seizures in dogs, uncertainties persist regarding quality control, contents of proprietary remedies, herb-drug interactions, and the impact of long-term use.
Courtesy of Dr. Narda Robinson.
Preparations of Herbal Medicine in Veterinary Patients
Botanical products come in a variety of preparations intended either for ingestion or external application. They may be fresh, dried, or freeze-dried; extracted and preserved in oil, alcohol, or water; and delivered as liquids, capsules, pills, poultices, or powders. The type of delivery method affects shelf-life, bioavailability, risk of contamination and adulteration, and acceptability to the recipient.
Courtesy of Dr. Narda Robinson.
The term "essential oils" refers to highly concentrated forms of plant-derived substances rich in terpenes or terpenoids. The use of these volatile, rapidly evaporating oils obtained from the leaves, stems, flowers, seeds, or roots of a plant by clients and some veterinary practitioners is growing despite minimal scientific evidence of effectiveness or safety.
Although certain essential oils such as lavender, administered via inhalation, have shown apparent value anecdotally for dogs as antianxiety agents, much remains unknown about safe and effective dosing, purity, and the consequences of chronic exposure. Considering the differences in olfactory sensitivity and the impact of scents on neurologic activity across species, diffused essential oils that people may find pleasant could negatively impact a dog or cat. Furthermore, essential oils pose a considerable danger to birds, with potentially lethal consequences.
Essential oils applied to the fur or directly to the skin may injure or kill an animal through oral ingestion or transdermal absorption. Examples of such dangerous oils include pennyroyal oil and tea tree oil, both of which have documented evidence of causing fatalities in small animals. As an indicator of its toxicity, pennyroyal has a long history of usage as an abortifacient.
Traditional Chinese Veterinary Herbal Medicine
The philosophical approach of the practitioner tends to dictate the type(s) of herbs prescribed. Science-based methodologies rely on pharmacologic evidence and translational insights to consider the pros and cons of assorted plant products for veterinary patients. In contrast, metaphorical and metaphysical approaches such as traditional Chinese veterinary herbal medicine tend to incorporate folklore and unvalidated diagnostic strategies such as tongue and pulse "diagnosis." They also rely on metaphorical concepts such as Yin, Yang, Wind, Heat, and Dampness to inform or determine product selection. In addition, Chinese "herbal" mixtures may contain endangered flora or fauna, as well as insects, worms, heavy metals, undisclosed pharmaceuticals, and a host of other ingredients. Furthermore, manufacturers may sell products as "proprietary," without disclosing each included constituent and its amount. This puts patients and practitioners at risk, especially when a veterinarian recommends a Chinese veterinary herbal remedy with undisclosed quantities of herbal strychnine (a potent neurotoxin) and/or aconite (cardiotoxic and neurotoxic).
Photograph of dried, sliced aconite (Aconitum carmichaelii) root. Like strychnine, aconite has also found its way into modern traditional Chinese veterinary herbal medicine preparations. Reports of deaths from arrhythmia and shock after ingestion of this toxic plant have not dissuaded some Chinese remedy manufacturers from selling veterinary formulae with aconite in undisclosed quantities. Veterinary personnel need to remain vigilant about the risks of Chinese herbs and to routinely inquire about the use of these and all other supplements.
Courtesy of Dr. Narda Robinson.
Photograph of seeds from strychnine (Stychnos nux vomica) tree. These seeds contain about 1.5% strychnine, a highly poisonous and intensely bitter alkaloid. Although strychnine has no recommended medicinal uses, some traditional Chinese herbal veterinary medicine remedies and homeopathic substances contain herbal strychnine in undisclosed amounts, putting veterinary patients at risk.
Courtesy of Dr. Narda Robinson.
Photograph of dried, sliced aconite (Aconitum carmichaelii) root. Like strychnine, aconite has also found its way into modern traditional Chinese veterinary herbal medicine preparations. Reports of deaths from arrhythmia and shock after ingestion of this toxic plant have not dissuaded some Chinese remedy manufacturers from selling veterinary formulae with aconite in undisclosed quantities. Veterinary personnel need to remain vigilant about the risks of Chinese herbs and to routinely inquire about the use of these and all other supplements.
Courtesy of Dr. Narda Robinson.
Photograph of seeds from strychnine (Stychnos nux vomica) tree. These seeds contain about 1.5% strychnine, a highly poisonous and intensely bitter alkaloid. Although strychnine has no recommended medicinal uses, some traditional Chinese herbal veterinary medicine remedies and homeopathic substances contain herbal strychnine in undisclosed amounts, putting veterinary patients at risk.
Courtesy of Dr. Narda Robinson.
Animal-based ingredients such as testes, penis, placenta, and horn found in Chinese “herbal” medicines harbor potential for zoonotic disease transmission. In addition to health concerns, animal-derived products in Chinese herbs contribute significantly to animal mistreatment and the endangerment of certain species. The unknown benefits of most mammal or insect ingredients do not appear to justify administering these agents to veterinary patients.
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