I have 2 cats and a dog. We got a new kitten about 4 days ago. One of my cats stopped eating, drinking, he vomited about 2 times today once time it was a brown liquid with a bit of food in it and the other was clear white liquid. The other animals are fine. I would say he's about 9 months maybe. He doesn't seem to dislike the kitten like my other cat. He hissed at first but then played with him a bit. Now he's been like this for about a day now. He was sleeping alot yesterday but today now I haven't seen him eating or drinking and he vomited about 2 times. I had another cat before who was stressed after I took him to petsmart ,atleast I think he was stressed, then didn't eat, drink and slept for about 2 days but he ended up fine. Only thing was he didn't vomit. So could this be stress or something more serious? I don't have the money right now for a vet so I'm hoping it's just stress. Update Friday: Today he went outside and came back to drink but he's not eating. I'm hoping that's a good sign that he's drinking again. And the vomiting seems to have stopped since last night.