OH yes, this is the stuff you need. I had a large carpeted room that had been thoroughly doused by several cats for a long time. As those of us trying to clean up strong, old pet stains in carpet have learned, regular cleaning chemicals -- and even many specialty "enzyme" cleaners-- don't do the job. Or they seem to for a while, then the smell returns with a vengeance.
After researching and trying several solutions, I happened to read about "My Pet Peed". The name definitely caused me to pause but I'm glad I ordered it. I started with a quart size which took care of almost all the stains, but then ordered a gallon to take care of those last two seemingly impossible spots.
The photos may not be too clear, but they show a part of the carpet near a door before and after the MPP was applied. In this case there was a lot of foaming, but after an hour you can just walk away as it leaves no discernible residue -- and best of all: NO SCENTS OR FRAGRANCES! Just a clean smell remains.
(Adding this note a little later...I want to add that it does also work great for FRESH accidents.)