Methylparaben and Polyparaben are very common food preservatives used to keep the product safe from bacteria, yeast and mold growth that could actually bring harm to your dog. These ingredients are completely safe when used in such small amounts [0.04% in chew which is 0.004 mg (4/1000) in small treat]. When we formulated these alongside veterinarians, we were careful to select only those ingredients that would not be harmful to your beloved pet. This product was designed by vets and safe for your pet to consume. The preservatives that we are using are approved to be used in supplements and we are adding them at a rate that is safe for all animals.