Pet dermis sells counterfeit products sourced from overseas. The packaging did not look legitimate so I called Merial and they told me that the lot number was invalid and they told me to look for certain package markings that would be on legitimate packaging. I emailed Pet Dermis and requested a refund and told them that Merial indicated that the product was counterfeit but they refused to refund my money. The EPA warns against using these products and I have filed a complaint against Pet Dermis with the EPA.