Some pets, like people, can be sensitive to certain ingredients, even if they're plant powered. That's why we see things like sesame allergies in pets and people. It's also the reason it's important to spot test any new product you use on your pet. Wondercide products are not waterproof so if you suspect your pet is experiencing an allergic reaction, gently rinse with soap and water. Consult your veterinarian if sensitivity conditions persist.