Caution When Using Herbal Remedies for Pets

With so many people turning to natural remedies to treat themselves and their families, it comes as no surprise that many pet owners are also interested in herbal supplements for their dogs and cats that pose fewer risks of side effects.

In the United States, there is a growing number of holistic vets who take the entire pet into consideration, not just their acute symptoms. The best of these vets subscribe to an online database and discussion forum run through Cornell University where they can look up the latest research from the top veterinary school in the country and also get advice from staff and colleagues. It is through this growing body of shared knowledge that we are coming to know what is safe for pets and what isn’t. Here are a few common botanicals used by humans for health that should not be given to pets.


Garlic is great for heart health in humans, but it can be lethal to cats and dogs. Garlic is part of a class of vegetables known as allium vegetables. They include onions (see below). Garlic damages a pet’s red blood cells and causes gastric distress, such as nausea, vomiting, drooling, and so on. Certain species are even more sensitive to garlic, such as Shiba Inu, and cats have particularly extreme reactions. Garlic is estimated to be 5 times more poisonous than onions.


Onions add a lot of flavor to human food, but they are off the menu for dogs and cats for the same reason as garlic. There are a number of different types of onion to look out for, including chives, leeks, shallots, and green onions/spring onions/scallions.

Symptoms to look out for include:

  • Drooling
  • Nausea
  • Oral irritation
  • Vomiting
  • Diarrhea
  • Lethargy
  • Abdominal pain
  • Elevated heart rate and respiratory rate
  • Weakness
  • Exercise intolerance
  • Collapse
  • Pale gums

Garlic is 5 times more toxic, with similar symptoms. If you suspect garlic or onion poisoning, treat it as a medical emergency and follow the instructions here:

Willow bark

Willow bark has the same active ingredients as aspirin, which is toxic to dogs and particularly cats:

Signs to look out for include:

  • Vomiting
  • Diarrhea
  • Bloody vomit
  • Black-tarry stool
  • Respiratory changes
  • Hyperthermia
  • Weakness
  • Change in thirst or urination
  • Collapse
  • Weakness
  • Tremors
  • Seizures
  • Death

Keep all herbal medicines and over the counter remedies well out of reach of pets, preferably in a locked cabinet so kitties with deft paws can’t open the doors and start tasting what they find or knocking it on the floor for the dog to try.

Tea tree oil

This essential oil is found in many households these days because it is so effective in cleansing wounds and treating acne. However, even a couple of drops can be life-threatening to your pet. Do NOT apply to the skin to treat wounds, and the oil should NEVER be taken internally, even by humans.

Signs to watch out for include:

  • Low body temperature
  • Weakness
  • Walking drunk
  • Inability to walk,
  • Tremors
  • Coma
  • Increased liver enzymes
  • Death

Treat suspected ingestion as a medical emergency and follow the instructions here:

Basics of Dosing Medicinal Herbs

One of the main issues medical practitioners have in relation to herbal remedies is a lack of accurate dosing information. There are several reasons for this.

Hands-on healing

Herbal medicine is conducted through experience, and individual treatment plans. What works well for one person may not work for another.

The practitioner’s personal preference

Some herbalists have favorite remedies with their own tried and tested doses, but there is no uniformity across all herbalists.

No set dosages

Because there is very little detailed research on herbs and how they can be used to treat particular conditions, there are no set dosages the way there are with prescription drugs.

Purity and potency issues

If you make your own herbal remedies, there might be issues with how pure and potent the herbs are due to the way you harvest, dry and prepare them.

Labeling issues

If you buy commercial herbal supplements, you really have no idea whether what is listed is actually in the supplement and if the amount of active ingredient supposed to be in it is actually in. A detailed analysis of herbal supplements discovered around 90% did not match in terms of dosage. It was usually too low, but in some cases, it was too high, which has the potential to cause an overdose.


Some herbs have very little active ingredient and a lot of filler.


Non-organic herbs will not be as potent as organic ones and will be contaminated with pesticides and other harmful ingredients.

Growing practices

Certain countries like the US, Canada, the UK, and the European Union members have higher standards in terms of growing practices as compared with many other countries.

Drying and preparation

Drying herbs and preparing them is key to getting potent, non-moldy herbs that will be effective against various health conditions. There are few manufacturing regulations in many countries. Again, it’s best to stick to herbal supplements from the US, Canada, UK, and EU.

Knowing which herbs do what

There are hundreds of herbs and botanicals used in herbalism. There are also 4 main schools o herbalism:

  • Ayurveda from India
  • Traditional Chinese Medicine (TCM)
  • Celtic/Roman/European herbalism
  • Native American

The same plants can be used in all 4, for different purposes, so it is important to study the herb carefully and seek help from a fully qualified herbalist. They will probably have to adjust your dosage over time to achieve the optimum one.

Use a reliable database

Use a reliable database such as WebMD’s:

You can look up hundreds of supplements such as St. John’s Wort, and learn about uses, side effects, interactions, and suggested doses, if any. Users can also leave reviews at the site to help you learn more.

Start slowly

Read the label. Start slowly with one herb at a time, at the lowest suggested dose. Keep a diary of symptoms to see if you are getting any relief from the herbs. Gradually increase the dose as long as it improves symptoms but does not produce harmful side effects.