Sales of counterfeit "Advantage" and "Frontline" over the internet has led the EPA to issue a warning about purchasing these products from internet sources and from big box stores. At best these counterfeit products are ineffective, and at worst they can be toxic. Please see the following link for the EPA's warning regarding possible toxicity of counterfeit products:
If you purchase your Advantage or Frontline through Bishop Ranch Veterinary Center, you can be assured of its authenticity and purity. We place our orders directly with the manufacurer and our product is delivered directly to us overnight.