Cat vomiting

well, check if the cat looks ill or in pain of any kind. if his behavior is different - go to the vet! if not he might have swallow a hair ball or something like that.

if you think that there is something wrong with him - the best thing to do is go check the cat at the vet.

hope it was usefull!

Cats have a tendency to vomit every now and then. Cleaning up cat barf is an unavoidable part of taking care of a cat. You can just hope that he doesn't do it somewhere that will cause damage (on the furniture) or be hard to clean (behind a cupboard, under the bed etc). If the cat's owner has gone away the cat might be feeling bored or insecure, and this might be the cause of it vomiting. I wouldn't be overly concerned about it, unless it happens every day.

Check the vomit for hair. It'll look like a dark mass, so poke it with your finger to confirm it's hair by breaking it apart some. Of course, put it in a clear plastic baggy and/or use something disposable and pokey.

If there's no hair... tell the owner that they need to take it to a vet to get checked out. I dunno the implications of that scenario. Good luck!