Why are all my cats, young and old, throwing up bile and lethargic?

The most common reason for symptoms you are describing in a young cat is an intestinal obstruction. Young cats often eat things they shouldn't (like hair ties, rubber door stop ends, strings, etc). I suggest you have him examined by your vet. This can be very serious. ( http://www.petcoach.co/article/foreign-bodies-in-the-small-intestine-of-cats/ )

I would err on the side of caution and get them seen today if you can, tomorrow, especially if they don't seem better. The vomitus looks like a hairball to me, but it's hard to tell. They may have overeaten, but unless that's something they already do, given the opportunity, I don't see that being as likely as something else, possibly getting into something they shouldn't have. Your vet will do an exam, possibly bloodwork, and maybe more//other diagnostics depending on what they find. Based on these results, your vet will have a better idea of what's going on and be able to recommend a treatment plan if needed.

Poor cats. Yes cats can catch bugs and get ill just like people can. And since both were sick simultaneously, it has to be something they both got into and ingested or were exposed to. It is very odd that nothing has changed in their environment, so finding out the culprit is going to be tough. You also may want t check with the company that made the filter you just changed just to make sure no recalls exist. Also I would consider just changing the filter altogether just to cover every possibility here. Also make sure that there also isn’t any chance of them getting into medications in the home as well. Regardless of that, they should be seen by your vet if they are still not eating and unwell. That is a long time to go without a good appetite, especially for a cat, and at the very least the vet can give them anti-nausea medicine, antibiotics (if indicated), and fluids to treat for any undelrying dehydration. I hope your cats feels better soon. Best wishes and take care.

Considering his age and the signs you described, I would be concerned and recommend an immediate check up. Differentials are many, from gastrointestinal diseases (infection/inflammations often dietary related) to any disease that can spread systemically (causing lethargy for example) like infection, and anything that can cause pain/discomfort. Hope this answer was helpful, but please do not hesitate to contact us again on the forum or by requesting a consultation if you have any more questions or to discuss it any further. If this answer was helpful please let us know, this will be used to improve our service!

Hi there. I would be concerned about a possible toxin ingestion or something along those lines if both of your cats are suddenly vomiting and having diarrhea. Pica-the term for a condition you have described for an odd craving for nutrients can be a sign of many things, and with multiple signs it is honestly best to see your veterinarian for further testing before proceeding. I hope this helps and that they feel better soon!

There is a chance given the symptoms that this could be panleucopaenia, a highly contagious viral gastroenteritis in cats related to parvo virus in dogs. I would recommend testing at least one affected cat as if positive vaccines can help protect the others. Fluids and anti nausea medications can help

I recommend to have the kittens examined by the veterinarian with in the next day. Many times these kittens will be played with internal and external parasites. Changes in diet and viral infections are also possible causes. There are a few types of parasites which can be transmitted to humans so it is very important to make sure they are treated appropriately to keep the humans in the household safe. I also recommend to look into a trap neuter release program for the mother cat to help control the population. One female cat can have almost 30 kittens in a year and this can lead to disease outbreaks and sanitation concerns. Best of luck.