Source: https://www.amazon.com/Merial-Frontline-Control-22-Pound-Puppies/product-reviews/B00008DFGY/?_encoding=UTF8&camp=1789&creative=390957&linkCode=ur2&showViewpoints=1&sortBy=byRankDescending&tag=fleascience-20&linkId=FDH45SVOSVVN7TAZ