(6/2021) The short answer is some are and some are not.

Essential oils are very concentrated volatile (they evaporate easily) oils which are either distilled or extracted from plants. It takes a lot of plant material to derive the oils. They give off the characteristic fragrances of these plants. There are currently about 300 oils commonly used out of more than 3000 oils that are known. These oils differ from fixed oils like olive, corn, and coconut.

The volatile oils are found in such products as cleaning products, Listerine, turpentine, citronella, Pinesol, and Vicks’ Vapor Rub. There is a wide range of toxicity depending on the type of oil and whether it is dilute or concentrated.

These oils are made up of small fat-soluble molecules making them readily absorbed through the skin, gastrointestinal (GI) tract, and/or lungs. Most of them are metabolized by the liver. Cats who have delicate livers to begin with and any pet with a liver problem/condition can be at risk for liver damage, liver failure and even death. Feline asthmatics are at more risk with inhaled essential oils. There can be individual sensitivities for people, dogs, and cats.

The plants often look the same, but the chemical make-up of their oils is different. Some oils are safe, but some can be toxic to pets. The "dose makes the poison." The routes of absorption from safest to most dangerous are inhaled, skin absorption, and ingestion. Generally, a toxic dose will happen acutely rather than chronically. Injured or damaged skin can increase absorption. These products can also cross the blood/brain barrier.

GI side effects are the most common including salivation, vomiting, diarrhea, and lethargy. There can be seizures. Cardiovascular side effects include low blood pressure, elevated heart rate or lowered heart rate. Respiratory signs include cough, sneezing and bronchospasm. Body temperature can be lowered or elevated.

There is no regulation of these products for quality and safety. There is no control over what is actually in them. There is no EPA regulation for the so-called flea products. The FDA considers these products cosmetics. There can be uncertainty about what is actually in the bottle and whether it matches the label.

Types of essential oils

Penny Royal - This is one of the most toxic oils. There are serious poisonings in people and dogs. The oral and skin routes of exposure occur. Metabolites are severely toxic to the liver causing damage, failure, and possible death.

Citrus - They are mildly effective insecticides that work by drying out the insects. Phototoxicity is possible, but the reactive components are commonly removed. Toxicity is mild with possible GI upset.

Wintergreen and Birch - These oils have high levels of methyl salicylate which is related to aspirin. That is why they are used as topical muscle pain relief in people. In dogs, it is easy to ingest a toxic dose. Symptoms include vomiting, lethargy, liver toxicity, kidney toxicity, seizures, and death.

Cinnamon and Cassia - Undiluted, these oils can irritate skin and mucous membranes.

Eucalyptus - This can cause nausea, vomiting, neurologic signs, and respiratory signs. There is a characteristic odor on the breath and in urine.

Lavender - These are very popular in use for people and dogs. It has been tried to calm dogs when travelling. Luckily, it is not generally toxic.

Peppermint - Menthol is a well-known ingredient. Less well known, but more dangerous is pulegone. Often this component is removed. If it is not, toxicity can occur through the GI tract or skin absorption. Liver toxicity and seizures can occur.

Nose Work Dogs

Oils are used to scent train dogs. Generally, these oils are safe as they are used in small amounts. However, one must be careful that an entire bottle of the oil is not consumed. Some common oils are Birch, clove, and anise.

The dog may seek out the flavor in gum. This can be a problem because often xylitol is used as an artificial sweetener in gum. If the gum is consumed, a toxicity can occur. So keep gum out of reach.

What to do when there is an exposure

If a dilute product is inhaled, seek out fresh air. If a product causes problems through skin contact, wash it off. If a large amount causes exposure or it is a very toxic oil, seek medical attention right away.

A pet poison control center can give advice to an owner and veterinarian for a fee. Pet Poison Helpline 800-213-6680