We used the sergeants gold flea and tick (couple bucks cheaper) on our beagle mix (60 pound dog), and within about an hour the dog was licking everything in sight and choking and hacking. This very active and very healthy dog began pacing and salivating everywhere. He was in obvious discomfort and when we took him outside, he ate more grass than I have ever, in all my years of pet ownership, seen. He threw up but it did not ease his licking, pacing or heaving. He spent the next 24 hours very lethargic and again vomiting. We kept a close eye on him and thankfully he was eating and drinking, but he is not his usual self. We also put it on our other beagle mix, Katie, who also threw up but seemed to have less of the effect that Badger did (he kept trying to lick her and we had to keep them separated), I would not recommend using this product at all. We had been using front-line and have never had this problem before. My husband bathed both dogs and it seemed to ease the problem a bit but he is still not back to normal.