I just recently realized what made my 6 lb min pin so ill last year and it was Hartz Ultra Guard 5 to 14 lbs. I still have the 2 other doses but luckily did not use them. She was constantly shaking, staring up in the air for no reason, vomiting, diarrhea, no appetite, fevers, crying in pain when touched and so much more. We brought her to the vet numerous times and they could not figure it out. At one point they suggested a pet scan because her spine seemed to be the problem. She was on antibiotics twice and the last time was for about 30 days. Finally, after months, she started to get better. It was absolutely horrible and very expensive. I always use advantix for my dogs but this one time I decided to try this terrible product. What a mistake. I was lucky that my Zoey did not die. Please share.