This happened last summer, we have only had our tzu a year. We started using Hartz, for small dogs. Well, I put it on her and then started noticing how strange she was acting. She acted like it was itching and burning. Obvious something was wrong, I put her in a tub of water and had my husband rush her to the vet. MUCH to my suprise he said if we had not done what we did, she could have died. THIS scares me to death that this product is still being sold!