Are essential oils safe for dogs?

When diluted correctly, some essential oils are safe for dogs, but it is not recommended for pet owners to use essential oils on your dog except under professional advice.  Essential oils are not safe for cats.  

What are essential oils?

Essential oils are the oil extracted from a plant through various methods, most commonly steam distillation.  The purpose is to extract volatile compounds from a plant for its medicinal properties and distinct aroma.

The volatile compounds/chemical constituents in essential oils can be very beneficial to your dog for their anti-bacterial, anti-fungal and anti-itch properties.  However they're highly concentrated, and if not diluted properly can cause severe damage to your dog and sometimes death.

For example, tea tree oil is rich in ascaridole, terpinolene, α-terpinene, 1,2,4-trihydroxymenthane, α-phellandrene, and limonene.  These chemical constituents are regarded as contact allergens.

Does this mean tea tree oil is unsafe for my dog?

Yes and no.  If we dilute the oil then these constituents will not irritate the skin. If the oil is not diluted enough then it can be unsafe. So what is a safe dilution? 

Knowing how to safely dilute essential oils for use on the skin can be quite complex.  Let's take tea tree essential oil as an example.  When we use tea tree oil in a product we have to look at the percentage of each chemical compound in tea tree oil and calculate a safe level for use on the skin.  The safe level also varies for a leave-in or wash off product.  Then we also have to account for the fact that each crop of tea tree oil varies and so will its chemical compounds.  To understand how each crop varies the manufacturer and/or suppliers chemist will issue a Certificate of Allergens with each batch.  The Certificate of Allergens lists the precise percentage of each chemical compounds in that particular crop or batch that pose as a potential skin irritant.  We use this document to calculate the safe dilution rate.  This process gets even more complex when using a blend of different essential oils.

Using essential oils is a great natural alternative to synthetic fragrances, however natural doesn't always equate to safe.  Formulating with essential oils is very complex and only recommended under professional advice.