As someone with a major cat urine problem and have gone through gallons of this stuff, I thought it’d be helpful to leave a realistic review and share my story. I recently moved to a different apartment and the previous tenants had a cat. There was tons of cat hair around the apartment and wasn’t very clean overall, but I figured “no big deal, I’ll just clean it up and it’ll be like new” (spoiler: wasn’t the case at all). Another thing to mention is the carpet was replaced in the whole unit, except ONE room. I didn’t think much of it at the time because that’s a pretty normal thing in between tenants, but more on that later. Now, I’m not sure what sort of magic the landlord did while I was touring the apartment, as there was no smell of cat urine - at all. Didn’t even cross my mind. I move in a little bit later and everything is fine. Fast forward a few days and I notice a smell in the one bedroom where the carpet WASN’T replaced. I noticed my own cat was acting a little strange and sure enough I discovered he peed on the floor. Very foolish me at the time thought this was it, and having no knowledge on cat pee, I grabbed my carpet shampooer and shampooed the section of carpet where he peed. While I was at it, I figured, “Why not just shampoo this whole room?” Sure enough, that made it worse. This is when I went full detective mode on my hands and knees smelling every inch of the carpet while my cat is staring at me wondering wtf I’m doing. I quickly realized the smell extended far beyond where my own cat had peed. I ran to the internet and began researching the topic of Cat Urine as if I was writing a thesis on it. This is when I learned that when cat urine is rewetted, it reactivates uric acid to recrystallize and suddenly made sense as to why this entire room now reeks of cat urine - I just wetted the entire carpet with the shampooer. Two corners of this room in particular smelled extra terrible, and at this point there was no way my cat did of all of this on his own. I resorted to pulling up about a foot of the carpet and was instantly hit with the most rancid, stale, rotten cat urine smell. The entire carpet pad was stained, the entire subfloor was stained, it seriously was AWFUL. At this point, I connected the dots: the previous tenants had a SERIOUS cat pee problem, hence why the carpet was replaced. I went around the unit and smelled nearly every corner in the unit and another 3 corners smelled just as bad on the wall and baseboards in the rooms where the carpet WAS replaced. No idea why the last bedroom didn't get it's carpet replaced too, but it was obvious at this point there was a major problem, and if I owned the place, I’d be ripping out the carpet in the last bedroom. However, that isn’t an option, so I resorted to finding a solution that would work for now. The biggest takeaway is you need one very key ingredient to get rid of the problem: Enzymes There’s tons of enzyme cleaners. I started with Rocco & Roxie and the fragrance nearly took me out. Probably would have worked if I used enough, but only used 32 oz of it - not nearly enough and didn’t want to buy more because of the intense fragrance. I tried Skout’s Honor because of good reviews and realized once I got home it’s not even an enzyme cleaner. Sure enough, didn’t work. This leads me to Anti Icky Poo, and thankfully I think this will be my last product. (And HUGE bonus is that it comes in an unscented version - definitely recommend that version) One really important thing to point out is you need to follow the instructions, especially for major urine problems. It says right on the bottle you’ll need at least a quart for 1 corner and multiple applications may be necessary. Acknowledge this step! For me, this equated to needing literally GALLONS of this. The key to this product is absolutely dousing the affected area and letting it stay soaked. In my case, I poured about a gallon on one corner, let it sit for a whole day with trash bags on top to preventing it from evaporating, and after drying it was probably 95% better! Realistically, I’m sure there will always be some odor in this case due to the subfloor being stained with the urine. It’s not a miracle product that will suddenly replace your subfloors soaked with years of cat pee - it just does what it says. This was clearly a problem that is too long gone at this point and likely needs complete replacement of subflooring. But, like I said, this isn’t an option, so I believe this product dealt with my issue in the best way given the circumstances. Maybe at some point I'll buy some more, pull up the carpet, and try soaking the subflooring, but thankfully, the room no longer smells like cat urine, and the only way you even get any hint of a smell is if you stick your nose directly in the corner. Overall, this product is really great. It does exactly what it says it’s going to. It didn’t rip out my subflooring and replace it, but it doesn’t claim to. There’s obviously physical limitations to a liquid product. But for most issues, this will do what it claims to do. Just don’t spritz your carpet with a decade of cat pee embedded into it and expect it to work, you really have to use it very liberally.