Instruct: Classify a given review into positive or negative sentiment.
Query: Messy and didn't work

Unless you feed your dog canned food, this product is a pain to administer. I put the powder on my dog's dry food, and after 3 days his white beard had turned completely brown from the powder, and it did not wash out easily. After that I folded it in some cheese, but it's a ton of powder and this was messy, plus I don't like giving my little dog that much cheese. Why can't it just be a pill?I went on for 3 weeks and saw zero improvement, so I switched to a whitening eye wipe that seems to work better.