Instructions
Check the Frontline box for stickers claiming to state the EPA registration number and/or the required body weight of the animal in question for the product. If your box has these, it is not an EPA-registered Frontline, as legitimate Frontline packages do not have these stickers.
Take out the contents of the box. It should have the appropriate number of dosages and an instruction leaflet. The instruction leaflet should state directions for use; storage and disposal information; emergency numbers; first aid statements and precautionary statements.
Compare the lot number of the applicators to the lot number on the box and make sure they match. Also look at the information printed on the covering of the applicator tubes. The following information is printed on EPA-registered Frontline products: Merial (registrant's name) and Frontline, Frontline Plus or other product name; net contents (fl. oz.); percentage of active ingredient(s); and type of animal the product is for. "Caution," "Keep out of reach of children" and "See full label for additional directions" are also printed in English on the tube.
How to Tell Fake Frontline
Saving a few bucks on Frontline could actually result in you getting a bogus product or worse, a product that can poison your pet. Counterfeit pet pesticides are a growing problem in the United States. They are illegally being sold to unsuspecting pet owners through various outlets such as online retailers, auction websites and even through brick-and-mortar stores. The Environmental Protection Agency has set a list of identifying factors for true, EPA-registered Frontline products which can help keep you and your pet safe from potentially dangerous Frontline knockoffs.