About two weeks ago my husband and I noticed some fleas on our dog Sami. We saw the Hartz products at WalMart and decided to give it a shot-we figured there is no way they could sell something that would be harmful to the dog and so much cheaper then the stuff at the vet! We gave her the drops down the back as directed at about 4p.m. Around 8 or 9 we noticed her running into walls and staggering around the house. We thought it was a little bit weird but let it go. By the next morning she would not eat, was drooling excessively (she never drooled) and was staggering around. She was unable to walk up or down the steps to go to the bathroom. We called our vet and they said that Hartz Flea Medication has been known to cause neurological problems and seizures. We took her in to be seen immediately, by then she could no longer walk on her own. They looked at her and confirmed that she had severe neurological problems and had already gone blind. They said seizures would soon follow. They suggested trying to flush her out, but that they damage had already been done. 18 hours after we gave her the Hartz, we had to put her down. She was 2 years old.