If you have dogs and cats in the house, these are the recommendations on how to diffuse your essential oils in a safe way: only use 3-4 drops of a particular essential oil in a water based aroma diffuser (UltraSonic). Use no more than 4-6 drops total if using more than one essential oil, or use the amount in the diffuser recipes.
Be sure your aroma diffuser is in an area where your pet cannot knock it over. Always diffuse in an open area with the door open so your pet can leave the room if desired.
If your pet is sensitive to an oil you are diffusing, stop diffusing and get your pet outside for some fresh air. Contact your veterinarian if you are concerned.