List of Toxic Essential Oils

Unlike humans, dogs and cats lack the proper enzymes to break down and digest many essential oils.

Even then, experts say there are several pure essential oils you should avoid diffusing and direct use entirely.

You should always avoid any direct contact and never apply essential oils (deemed pet-safe or otherwise) directly to your pet's coat or skin.

Essential Oils that are considered Pet-Safe:

Cedarwood Oil: Natural insect repellent
Chamomile Oil: Helps calm the gastrointestinal system
Frankincense Oil: Soothes joint pain
Helichrysum Oil: Known for heart, skin, and coat benefits
Lavender Oil: Calming effect
Rose Oil: Calming effect
Peppermint Oil (use in moderation): Natural remedy against fleas & ticks

Here is a list of known harmful essentials oils to dogs and cats.

Phenol Oils (Anise Oil, Clove Oil, Basil Oil, Oregano Oil, Thyme Oil, Calamus Oil or Cane Oil, Cassia Oil, Cinnamon Oil)
Pennyroyal oil
Pine Oil
Tea Tree Oil
Citrus Oils (Oils that contain d-limonene, including Citronella Oil, Bergamot Oil, Grapefruit Oil, Lemon Oil, Lime Oil, Orange Oil, and Tangerine Oil)
Sandalwood Oil
Ylang ylang Oil
Menthol oils or mint oils (including Eucalyptus Oil, Peppermint Oil, Spearmint Oil, Sweet Birch Oil, and Wintergreen Oil)
Juniper Oil

More Essential Oils Toxic for Cats:

Basil Oil
Dill Oil
Fennel Oil
Geranium Oil
Lemongrass Oil
Myrrh Oil
Nutmeg Oil
Rosemary Oil
Sassafras Oil
Tarragon Oil
Wormwood Oil

This list is not exhaustive and you should inquire with your vet if you are using any essential oil, or essential based product. Information courtesy of 24PetWatch & Pet Poison Hotline