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: