Instruct: Classify Amazon reviews into positive or negative sentiment
Query: Ineffective

After her last UTI, my cat was consistently peeing on the floor next to the litter box, instead of inside it. My veterinarian suggested a Feliway diffuser. I tried it for the full 4 weeks, as recommended on the package, and it had no effect whatsoever. Moreover, each bottle of liquid only lasted 2 weeks, not 4 weeks as stated on the package, meaning I had to buy a refill just to complete the recommended 4 weeks. These things apparently work well for some problems, but it undoubtedly depends strongly on the root cause of the behavior. Another veterinarian later told me these things are "hit or miss." I can vouch for that.