Question: is peppermint oil in a diffuser bad for dogs?
Answer: Many essential oils, such as eucalyptus oil, tea tree oil, cinnamon, citrus, pennyroyal, peppermint, pine, sweet birch, wintergreen, and ylang ylang are toxic to pets. ... Oil from diffusers can still be harmful since the diffuser uses water vapor to diffuse tiny oil droplets into the air.