Instruct: Classify Amazon reviews into positive or negative sentiment
Query: This Stuff is Amazing

I have genetic chronic sinusitis. Had surgery for an infection that went berserk. Heard about grapefruit seed extract but only found it recently. I spray 10-15m before going to bed and it makes a huge difference; I can breathe through my nose while I am lying down. It does burn a tiny bit, but for what it does, it's laughable to consider the cost/benefit.