Cat sounds like a sniffing dog sometimes

It happened once because someone used air freshener and I've seen it happen after eating sometimes. Took him to the vet. She didn't find anything wrong. What could this be?

Not too sure on this one and may need a little more description/information. Does the cat sniff as if it were going to sneeze - rapidly? It could be something such as allergies or a very sensitive nasal passage to certain smells and then overreacts by inhaling quickly? :dk: Good that you brought your cat in for a check-up and that should ease you mind up a bit. If you can get a video of this somehow that would help so you could show the vet. I know that can be very difficult though. I have a cat that has asthma and by the time I get the phone to catch a video, he stops the breathing episode. I wouldn't worry too much as long as your cat is eating, drinking and otherwise completely normal. If this continues and progressively becomes more active, then get that video and have the vet reassess your cat! You can even post it here if you like.