After moving into my new house, I accidentally locked one of my cats into the only room that has carpet in it over night, and it pissed in the corner. I tried just about everything to get rid of the smell with no luck... then I tried hydrogen peroxide. Apparently its not the cat piss that smells, but the bacteria that feast on it. I tried just a little, and the smell went away for about a week. Then I dumped an entire bottle all over the entire area... no more smell! I'm not sure if it would work with dog vomit... but it could be worth a shot? For what its worth... the hydrogen peroxide didn't bleach/stain my carpet... so I would assume it'd be fine on your carpet/seats...but who knows?