This is an interesting article that appeared in my paper yesterday. I seriously thought I was going nuts. I had been using Frontline for years but last year it stopped working on my dogs. I thought I got a bad batch and bought more but that didn't work either. I ended up switching to Advantix and it works great. Here is the link if you want to read it there: http://www.beaufortgazette.com/local_news/story/6244907p-5452352c.html Here is the article: Flea treatment Frontline falls out of favor Veterinarians switch to recommending Advantage, K9 Advantix Published Wed, Nov 22, 2006 By PETER FROST The Island Packet Comments (0) Add Comment One of the most common brands of flea treatment for pets is falling out of favor with many veterinarians. The veterinarians say they have stopped prescribing Frontline brand flea and tick products in favor of other brands like Advantage or K9 Advantix, which are proving to be more effective. A survey of six Beaufort County animal hospitals and veterinary clinics revealed that all recommend either Advantage or K9 Advantix products to treat flea problems on dogs and cats -- a significant change for some of the offices, which as little as a year ago prescribed Frontline-brand medications on a two-to-one ratio over all other treatments. "In our office, we've seen 25 percent more skin problems related to fleas this year in what appears to be a failure of Frontline," said Dr. Ben Parker of the Coastal Veterinary Clinic in Bluffton. "In most cases, it's simply not working." Susan Ralston, a senior field veterinarian with Frontline's manufacturer, Duluth, Ga.-based Merial Limited, a joint venture between Merck & Co. and Sanofi-Aventis, said Frontline has "great products that do exactly what they're supposed to do." "This is not an isolated issue with Frontline," Ralston said. "All companies this fall have been challenged by the sheer number of fleas you've got in that area this year." Parker said Frontline Plus, an ointment to protect against fleas and ticks, was his top recommendation for pets earlier this year. But now, he said, he's almost exclusively prescribing Advantage, which protects pets against fleas, or K9 Advantix, which protects against fleas, ticks and mosquitos. Some veterinarians and researchers say problems with Frontline products surfaced in isolated incidents during the last two years, but not until this year have the issues become widespread. Veterinarians interviewed for this story in South Carolina, Georgia, Florida and Iowa said they've had problems this year with Frontline. "At first, we thought there may just have been a bad batch of the product," said Dr. Nancy Hinkle, professor of veterinary entomology at the University of Georgia. "But now, we're receiving reports from three different states, and all customers were complaining that the materials weren't working. "It leads me to believe there's another explanation. It leads me to think there may be incipient resistance." Hinkle and other veterinarians said it's possible fleas have built up a resistance to one of the active ingredients in Frontline, causing the products not to work. Ralston said there's no evidence that there is any resistance in the field to Frontline or any other products on the market. She said Frontline is caught in a perception problem. "People need to realize that fleas have to get on the pets for any of the products to work," she said. "Just because there are fleas intermittently on your pet doesn't mean the product's not working." In nearly every case, she said, flea problems can be traced to either an environmental factor, such as bedding infested with fleas, or a skin problem with the pet that doesn't allow for the product to evenly distribute. "They need to look at the bigger picutre of what's going on in these particular cases and get to the bottom of the problem," Ralston said. "They shouldn't just throw their hands up and say 'Well, it must be the product.'" Though each medication is applied between an animal's shoulder blades, Frontline Plus, Advantage and K9 Advantix use different active ingredients. Frontline Plus uses two ingredients: fipronil, which kills adult fleas, and methoprene, which prevents the development of flea eggs and larvae. Both Advantage and K9 Advantix use imidacloprid, which paralyzes and kills fleas on the animal's body. K9 Advantix adds permethrin, a pesticide that kills and repels parasites. "There's definitely awareness and a lot of anecdotal evidence that Frontline's not working," Hinkle said. "And though there are a number of research projects testing insecticide resistance in fleas, there's been nothing published that's validated or proven that."