No known side effects. Use only on dogs. Avoid contact with dog's mouth, face, eyes and genitals. Do not use on puppies below 12 weeks of age. Consult veterinarian before use on debilitated, aged, medicated, pregnant, or nursing dogs. Avoid use of product on dogs simultaneously or within 30 days before or after treatment with or exposure to cholinesterase inhibiting drugs, pesticides, or chemicals. Observe dog for a few days for any adverse reaction to the collar such as skin irritation. If irritation occurs, remove collar and consult veterinarian