My cat vomited after new kitten arrived. Is it stress or illness?

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!

I am sorry to hear this! Yes, it is possible he picked up something from the new kitten even if she was asymptomatic. I would recommend taking them both in and having them tested for infectious diseases and worms at a minimum. I hope it is nothing too serious but better safe than sorry! I hope this helps!

Pets can vomit due to stress but with an older cat, it's very important to make sure there's not a health issue going on like hyperthyroidism or renal disease. I recommend to play it safe and have Harley examined by the veterinarian. If he is eating the kitten food, this could also cause the vomiting. If the vet thinks this is stress related, there are a few things you can do to help Harley feel less stressed. Here is a great article about cat's instinctual needs: https://www.petcoach.co/article/why-every-cat-needs-a-place-to-climb/ Use a Feliway diffuser, set aside 30 minutes a day for vigorous play for both cats and/or switch the food to Royal Canin Calm (for Harley, not the kitten). Make sure Harley has some quality alone time and is not being bullied by the kitten. Most cats response best to combination therapy. The veterinarian can also prescribe medications which can help with stress if needed. I hope this helps and please feel free to post any additional questions.

No, this is not a reaction to the death of the other cat, it is a medical condition, most probably a gastrointestinal infection. i would recommend taking him to the vet the first chance you get, he will need to be checked first, if the vet thinks it's a simple gastrointestinal infection he will need an anti vomiting injection, antibiotics and a special food for a few days in order to get better.

Stress can sometimes cause a cat to vomit, however if you notice one of the cats is getting ill a lot, is rapidly losing weight, or is showing other signs of illness such as refusal to eat or drink, extreme lethargy, etc, then seeking vet care is a good idea to figure out the problem.

Hello, sorry to hear about Hikaru. I would actually ensure that there isn't anything else going on with your eldest. Some cats can have a hypersensitivity or an allergy to certain types of food. Typically, these kinds of allergies can be treated by changing the type of food with a new food that contains a different kind of protein. You can also try a food with hydrolyzed protein (hypoallergenic), though this kind of diet can be more expensive. Otherwise, you should ensure Hikaru is not losing weight, having diarrhea, or has a decreased appetite as all of these may indicate a more aggressive disease such inflammatory bowel disease or GI lymphoma. If you note any of these as well, you should have Hikaru evaluated by your veterinarian soon. Best of luck and hope this helps.

The possible causes of for vomiting are numerous. The fact that you recently moved (be in a month ago at this point) could play a role potentially as stress is a definite cause of GI upset in cats. Other causes can be dietary, gastroenteritis, pancreatitis, kidney / liver disease, allergies, foreign objects, and even cancer in some rarer cases in a young cat. Since there have only been episodes of vomiting total at this point, I wouldn't be particularly concerned as of yet. If you see this happening another couple of times over the next week, I think it is something worth investigating more. Hope this helps!