I used a 1/2 dose of Hartz round worm medicine for my 3 month kitten. After a half hour her eyes glazed over and she was unsteady and jittery. She was out of sorts and didn’t want to be near us for over three hours. It was like she didn’t know us. Thank goodness she is better this morning. That’s when I started googling the product and saw all off the similar stories. Spread the word. BAN HARTZ PRODUCTS!