Ticks really do not like essential oils. They search out pets and people by scent, so essential oils work not only by masking a dog’s scent, but some essential oils actually repel them. Geranium is on the top of the list for repelling ticks, along with lemon eucalyptus, and lavender (study here). Lavender oil has even been shown in studies to prevent tick eggs from hatching.
This tick blend can be mixed with a carrier oil like grapeseed and rubbed into a pet’s fur and legs. Essential oils are too strong to be put directly on the skin without causing irritation, so diluting with a carrier oil (an unscented oil) lets essential oil be used on the skin without irritation. For using oils topically on dogs for tick or flea prevention, a good dilution is roughly five drops of essential oils mixed with a teaspoon of carrier oil and then rubbed into the fur- being careful to avoid the eyes, nose, mouth, and genitals.
These oils can be mixed and then put on the outside of a collar if it is made of an absorbent cloth.
Pennyroyal oil is very effective as a tick repellant, but even though many recipes online recommend using pennyroyal for pets, pennyroyal can be toxic to the point of death for dogs and cats. For that reason, even though pennyroyal is an effective tick deterrent, we do not recommend using it topically for dogs or cats. If you still do desire to use pennyroyal for dogs, a very small amount (1-2 drops) can be applied to the outside of a collar to repel ticks (make sure the oil is absorbed into the collar before putting it on). Pennyroyal should never be used on cats, and only for dogs with caution.
Safer oils to use that repel fleas are eucalyptus, peppermint, cedarwood, and citronella.
To make an essential oil spray for dogs, combine 30 drops essential oils to one cup of water and to spray on a dog’s fur. Shake bottle well before spraying each time to mix the water and essential oils. For small dogs, reduce the amounts of essential oils in this recipe.
Geranium oils and citrus oils should not be used on cats, in fact, cats are particularly sensitive to essential oils, so this recipe is best used for dogs. Also, essential oils like pennyroyal, cedar, and citronella should not be used on pregnant animals (on any pregnant animal, it is best to use oils only on a collar, rather than on the skin). Animals should never ingest essential oils.
Cats and Fleas and Ticks
For cats, the one oil that they seem to be able to tolerate is neem oil. Neem can be helpful for both fleas and ticks for cats. A small amount can be added to a shampoo (at the dilution of no more than a teaspoon of oil to a cup of pet shampoo). Neem can also be used in small amounts on the outside of a cat’s collar as a flea repellant.
Geranium and rosemary oils can be used as a flea and tick repellant on cats, as long as they are highly diluted. For a flea and tick spray for cats, mix 4 drops total of geranium and rosemary oils to one cup of water and spray on cat’s fur, avoiding the face.