Warning

• Since peppermint oil and peppermint plants can kill cats, do not use in homes with cats. Symptoms of peppermint poisoning in cats include liver damage, vomiting and diarrhea.
  
  

Speculation

• Peppermint oil is thought to deter mice because of its smell. But smell-based deterrents, including moth balls, only work for a short period of time, so are not effective long-term solutions.
  
  

Considerations

• Rats and mice do not seem to like the taste of unsweetened peppermint. Fresh peppermint plants grown in the garden can help deter both mice and rats from eating flowers or vegetables.