I applied Sergeant's Senrty Pro XFC to my 1 1/2 yr old boxer. Since I have used several spot-on flea controls before, I knew not to apply it too far down his spine as he is extremely flexible and can lick parts of his back. I was very careful not to put it on an area that his tongue could reach. I applied the product at 6:00pm. At 7:00pm, the dog was fine. We had a gathering to attend, so I placed him in his kennel. Upon returning home at around 11:00pm, I let the dog out to potty. I noticed he was salivating...A LOT! He ate, drank, went... read full review »