Cats and Essential Oils

Aug 2, 2018

Introduction

Essential oils have become increasingly popular in recent years. While their use is widespread, information about their health and safety effects is sparse and often contradictory. This is especially true when discussing their effects on cats.

There are misunderstandings about what essential oils are and what steps need to be taken to ensure they do not harm pets. There are many types of essential oils, each with their own unique physical and chemical properties.

Asking, “Are essential oils safe?” is similar to asking, “Is medicine safe?” or, “Are plants safe?” The type of oil, dose, and route of exposure all determine the answer to this question. This document is meant to provide an overview of this topic so you can make informed decisions about essential oils. It is not intended to be an exhaustive source of information and is not meant to be inclusive of all essential oils and their risks.

Please contact your veterinarian for guidance regarding exposure to essential oils and their potential for adverse effects.

What are essential oils?

Essential oils are extracts of plants that contain a large amount of volatile (easily evaporating) oil. They are extracted and concentrated by distillation or cold pressing. The smell and taste of plants are often determined by the essential oils they contain. Essential oils may be sold on their own or used in other products. While many people think of diffusers, cosmetics, or potpourri when they think of essential oils, insecticides, paint thinner, and flavoring agents also make use of these compounds.

What studies have been done on long-term effects of essential oils on people and pets?

There is a lack of information about the impact of many essential oils on the health of pets. As a result, people often rely on opinion rather than facts. Some state that essential oils are largely safe because no increase in hospitalization has been seen as they become more popular. Others state that side effects of their use may be subtle and cumulative in lower level exposures and conclude the safety data are insufficient for the purposes of the safety assessment. There are several reported cases of direct exposure to certain oils causing harm or even death.

There is very little published experimental data on the toxicity of essential oils to cats. This is due in part to the variety of essential oils, the lack of funding for such studies, and the ethics of exposing animals to potentially fatal substances. Data on chronic or low-grade exposure is even rarer. As a result, much of the evidence-based information is based on case reports or theoretical toxicity based on chemical properties.

Why are we talking about cats and not dogs?

Dogs are also susceptible to certain essential oil toxicities, but cats are much more so. Cats’ livers are deficient in a process called “gluconuridation”, an important step in the metabolism of many compounds. As such, chemicals that are metabolized by other species often accumulate or are broken down into toxic metabolites in cats. This is especially true for compounds called “phenols” which contain an “aromatic” or “benzene” ring. Many essential oils contain phenols, and, as such, may be poisonous to cats. These may lead to liver failure, seizures, or other serious issues.

Cats’ small size means they are susceptible to poisoning by smaller volumes of oil and their tendency to groom themselves means skin contact often leads to oral contact. Cats also have a very sensitive respiratory tract, being prone to reactions to inhaled substances such as smoke. As a result, they are more likely to develop respiratory distress when exposed to volatile oils.

Toxic effects of essential oils

Exposure to essential oils may be oral, through inhalation, or even through direct absorption through the skin. Some essential oils can induce a reaction that is not directly “toxic” by triggering allergic reactions. Cats with asthma, chronic upper respiratory disease, skin allergies, or other similar conditions may experience an exacerbation of clinical signs when exposed to essential oils. In the case of asthma, these reactions can be serious or even fatal.

Cats can also develop watery, irritated eyes and noses from chemical irritation of the respiratory or eye lining membranes, or develop dermatitis from direct skin contact. In people, essential oils are increasingly understood to produce positive patch tests for hypersensitivity—lavender and tea tree oil being the most commonly cited examples.

Other oils may be more directly toxic, causing failure of the liver, kidneys, heart, or other organs.

Which oils might be toxic?

Making a list of toxic versus non-toxic oils has limited use because potential toxicity depends on the route, rate, and amount of exposure, as well as the supplier quality and the other compounds that are in the preparation of a brand of oil. Not all published lists include the same oils since there is a shortage of published scientific studies. Many of these “toxic oils” listings are based on testimonial and first principles of how species and chemicals are expected to cross-react, with reference to rare and scattered toxicity case reports. Therefore, these lists are not very accurate. A comprehensive listing of plant toxicities, such as provided by the ASPCA Poison Control Site might not specify whether it is the plant or oil extract in many cases. Below is a tentative list for general information, but further research is needed to test accuracy of this and other listings, as this information has not been evaluated by any government agencies.

This list has been pooled from various sources and is not exhaustive (and it is not presented in any order of toxicity):

Bergamot (Citrus bergamia; Citrus Aurantium)
Bitter almond (Peumus boldus)
Calamus essential oil (Acorus calamus)
Cinnamon
Clary Sage
Clove (Syzgium aromaticum)
Eucalyptus (Eucalyptus spp.)
European Pennyroyal (Mentha pulegium)
Geranium oil (Pelargonium sp.)
Horseradish (Amoracia rusticana)
Japanese yew (Taxus spp.)
Lavender (Lavendula angustifolia)
Lemon oil (Citrus Lemonia) citronella
Lemongrass (Cymbopogon citratus)
Lime oils (Citrus aurantifolia)
Mustard
Orange oils (Citrus sinensis)
Oregano (Origanum vulgare hirtum)
Pennyroyal; American false pennyroyal (Haedeoma pulegioides)
Pine, spruce, juniper oils
Rose
Rosemary
Sandalwood
Sassafras
Tea tree (Melaleuca alternifolia)
Thyme
Wintergreen, peppermint, spearmint, mint (Mentha sp.)

Wormseed

Ylang Ylang

Essential oils come in many forms and are found in some household products. Toxicity has been reported due to exposure to certain home cleaning products, as well as direct exposure to essential oils.

What are signs of overexposure?

Signs of toxicity will depend of the dose and type of oil, but often include changes in mental status (dullness or lethargy), neurologic signs (wobbly, trouble walking, weakness, tremors, seizures), digestive signs (drooling, vomiting), and physical signs such as the animal pawing at their face, red areas on the skin or mucous membranes, respiratory distress (trouble breathing, coughing), cold body temperature, slow heart rate, and death.

Quality control of essential oils is not overseen by government regulatory agencies, so some preparations may have varying levels of active ingredients and may not contain the ingredients described. Oils are suspended in different types of solutions that may be toxic.

Can I use essential oils if I have cats?

As with many things, the ultimate answer to this is, “It depends.” Factors such as the type of oil, method of use, concentration, and individual cat sensitivities play a role in the risk of essential oil toxicity.

There is mixed opinion on the use of vaporized or aerosolized essential oils. While the risk of acute toxicity is low with inhaled oils at low concentrations, some people believe there is the possibility of long-term cumulative damage that may increase the risk of liver and lung diseases. Others believe this risk is insignificantly low.

Some general guidelines to the use of essential oils in homes with cats are as follows:

Never apply essential oils directly to cats, feed oils to cats, or leave oils in areas where they may come in direct contact with cats.
While some oils do have insect/pest repellant activity, the risk of serious or fatal reactions in cats with these oils is high, and very safe and effective alternatives exist.
Avoid the use of the oils on the above lists pending further research.
Avoid the use of essential oils in households with cats with asthma, allergies, or similar conditions.
Keep cats out of rooms with a high concentration of essential oils (when paint thinner is used, floors are washed, or diffusers are used without open windows, for example).

What to do about exposure?

Take your pet, along with the product packaging, to a veterinarian immediately if you suspect exposure to a noxious essential oil. Do not try first aid such as induction of vomiting or giving home charcoal therapy. Some oils may cause damage to the esophagus and may be fatal if vomit is inhaled. If a cat gets essential oil on its paws or fur (e.g., spilled diffuser or bottled essential oil), wash it off with bland soap and water, rinse well, and call your veterinarian right away for further advice.

Immediate veterinary support may be needed in some exposures. Poisoning effects are variable and your veterinary healthcare team will develop a treatment plan suited to your particular circumstance. Call a clinic immediately if you see any concerning signs such as seizures or difficulty breathing.

Blood tests and admission for care with intravenous fluids, breathing support, pain control, other medications, and nursing care may be required depending on dose and type of exposure. The prognosis after exposure will vary based on the type of oil, dose, and amount of time between exposure and getting care.

Please contact your veterinarian with any specific questions regarding essential oils.

Kathleen Cavanagh, BSc DVM MET
Consulting Online Editor CVMA

Matthew Kornya, BSc, DVM, Resident ABVP
Consulting Editor

July 31, 2018