Instruct: Classify a given review into positive or negative sentiment.
Query: Horrible Reaction

I can't believe this is still on the market. I used once on my dog and he had a horrible skin reaction that lasted for days. His skin became red and irritated, he wouldnt let me come near him, and was whimpering. Even after repeated washings he was sore to the touch. I now use frontline or get the Rx for first shield. Do NOT buy if you care about your pets health.