A few months ago we went to Wal-Mart and bought the Hartz ultraguard flea & tick drops for dogs. We waited until that night to apply it. When we applied it she was fine, and about 10 minutes later she started falling on the floor and staggering around everywhere. Almost like she was drunk. I quickly realized she was having a reaction to the medicine and picked her up and tried to calm her down. She then started to move her head in erratic circles, as if she couldn’t control it. Her eyes were glazed over also. I ran to the bathroom and bathed her as fast as I could! I didn’t know what else to do. I could barely hold her to wash her because she couldn’t stand up, and she kept falling in the water. After I washed her as good as I could, I wrapped her in a towel and sat in the bathroom floor with her. I was just hoping she wasn’t about to die! She continued to have convulsions for a few minutes, and then it finally stopped. She had 2 more after that but they were not as bad as the 1st one. We even tried calling Hartz customer service for some kind of advice while this was happening. We told them our dog was having an allergic reaction and she was acting like she was about to die. They acted like it was NOTHING! They put us on hold for about 15 minutes while the lady went and talked to her “manager”. After we waited on hold, she came back and told us to take her to the vet. That was it! I mean if I would have had that option I would have done it in the 1st place, but it was in the middle of the night so no vet was open, plus I live far away from the nearest vet. So our only option was to call them. I will NEVER EVER EVER use that stuff again! It is poison to the poor animals! And it almost killed our baby! Please do not EVER use these products! Try using Dawn dishwashing liquid. It is completely safe for animals and it also kills fleas and ticks. We have been using it ever since and it works very well!