When it comes to finding the best indoor spider repellent that is also pet safe, you have to be very careful about using essential oils around cats and dogs. Certain types of essential oil can be very toxic if ingested (which is why humans also use carrier oils to apply them to their skin) so these suggestions may not be appropriate for your four-legged friends. For example, cats can be harmed by coming into contact with tea tree, thyme, oregano or cinnamon, while dogs can have adverse reactions to juniper, anise, clove and thyme. For more information about using essential oils around pets, read our blog on how to use them safely.