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My cat is vomiting yellow bile and grass. Is it stress from new cat?

Updated On September 23rd, 2025

Pet's info: Cat | Domestic Shorthair | Male | neutered | 8 years and 3 months old | 7 lbs

We had a young community cat follow my adult (primarily indoor) cat home 5dys ago. The little one is obsessively attached to my adult cat and he is very annoyed w/the little one though he seems to be adjusting. However, my adult cat has vomited yellow bile with grass 2dys in a row. Before the new kitties came my cat would occasionally vomit the same after being out at night. He was out last night as well. I still believe he is stressed frm new kitty but concerned of his physical health.

1 Answer

Most Helpful Answer

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Answered By C. Rathjens, DVM

Veterinarian

Published on October 27th, 2018

Stress is definitely very possible. It sounds like you're planning on keeping the second cat, so I would recommend separating them, taking the new guy to the vet for vaccines, testing for viruses, and a general check up (take your adult cat as well, on a separate day, if the vomiting continues) and then SLOWLY introduce them over 1-2 months. Some cats never really adjust to a new cat in the household, so be aware that this might not go well. Good luck!

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