Instruct: Classify a given Amazon review as either positive or negative.
Query: No longer works.

I used this product successfully for years however it no longer works. I even applied a second dose after only two weeks hoping for a cumulative effect but no joy. The cats still have fleas. I suppose one upside is the fact that I haven't found any ticks on them even though I live in a tick infested area and the cats do go outside.That said, I'm going to go a different route before the little bastards give me bubonic plague.