This started three days ago. I noticed that my cat is not eating. When he does eat, he cries, then he throws up and it looks yellowish in tint. Earlier I put food down for my other cat and I guess because of the smell of it he started to cry then throw up again. This time it wasn’t as yellow. Could you please help me? My cat is six years old. I do have a two year old cat living in my house as well but my two year old cat is not vomiting at all. Also, my cat that is vomiting has not gone to the restroom either. When he goes inside his litter box, he tries to throw up as well. The only thing that comes out of his mouth is foam in there.