If your cat is having trouble breathing, has collapsed, is straining to urinate with little or no output, is having a seizure, has been in an accident or fall, is bleeding heavily, or may have eaten something toxic (including lilies, which are highly toxic to cats), stop reading and contact an emergency veterinary clinic now. For suspected poisoning, the ASPCA Animal Poison Control Center (U.S.) can be reached at (888) 426-4435 (a consultation fee may apply).
For everything else, this guide organizes common warning signs by urgency. It's general information, not a diagnosis — a symptom below is a reason to get your cat checked, never a confirmation of a specific condition. That distinction matters even more with cats than with dogs, for a reason worth understanding first.
Veterinary disclaimer. This article is general, informational content. It doesn't diagnose your pet's condition and doesn't replace an in-person veterinary exam. See the full Veterinary Disclaimer.
Why cats are harder to read than dogs
Cats are much better than dogs at masking discomfort. According to Dr. Stacy Eckman of Texas A&M's College of Veterinary Medicine, this is believed to be a survival instinct: in the wild, an animal that visibly shows weakness is more vulnerable to predators, and that instinct persists in domestic cats. In practice, this means many cats don't show obvious pain or distress until a problem is fairly advanced — which is exactly why subtle behavior changes deserve more attention in cats than they might in dogs, and why routine annual (or more frequent, for older cats) veterinary visits matter even when a cat seems fine.
Urgent: contact an emergency vet now
| Sign | Why it's urgent |
|---|---|
| Difficulty breathing, open-mouth breathing, or blue/pale gums | Cats rarely pant like dogs do; labored breathing is a serious sign |
| Straining in the litter box with little or no urine, especially in male cats | Can indicate a urinary blockage — a true emergency that can be fatal within 24–48 hours if untreated |
| Collapse, extreme lethargy, or inability to stand | Can indicate a range of serious underlying issues |
| Seizures, or repeated seizures | Needs prompt evaluation |
| Not eating or drinking at all for more than 24 hours | Cats that stop eating are at risk of a serious liver condition (hepatic lipidosis) that can develop quickly |
| Suspected ingestion of a toxin, including lily plants (all parts, including pollen and vase water, are highly toxic to cats) | Some toxins cause organ damage within hours |
| Persistent vomiting or diarrhea unresolved after 12–24 hours | Cats dehydrate and decline faster than dogs relative to their size |
| Sudden hind-limb weakness or paralysis, or extreme pain vocalization | Can indicate a cardiac or vascular emergency |
Soon: book an appointment in the next day or two
These are subtle behavior changes that Texas A&M's guidance identifies as the kind of signs an owner is most likely to miss, precisely because cats hide illness so well:
- Sleeping noticeably more than usual, or in unusual positions/locations, and staying there for extended periods.
- Withdrawing from normal affection, or resisting being touched or picked up in a way that's out of character.
- Not greeting you at the door or coming when called, when that used to be typical behavior.
- A change in litter box habits — going outside the box, straining, urinating more or less frequently, or noticeably different stool.
- Vomiting more than an occasional hairball.
- A change in appetite or water intake in either direction.
- Hiding more than usual, especially for a cat that isn't normally a "hider."
Worth mentioning at your next routine visit
- Gradual weight changes (see our guide on telling if your dog or cat is overweight).
- Mild, occasional decrease in grooming, or a slightly duller coat.
- Small changes in activity level in an older cat.
- Bad breath or visible tartar (a sign to also review our dog dental care guide for the general prevention principles, which apply to cats as well, even though that guide is framed around dogs).
Why routine vet visits matter for cats specifically
Because cats are so good at masking symptoms, annual wellness exams (and more frequent visits for senior cats) are one of the only reliable ways to catch problems early. During a routine exam, a veterinarian can pick up on weight changes, subtle findings on a physical exam, and recommend bloodwork as your cat ages — catching things well before they'd be obvious at home. This is a case where "my cat seems totally fine" isn't the same as "my cat has no health issues."
FAQ
My cat has always been shy and hides a lot — how do I know if new hiding is a health issue? The key is a change from your cat's individual baseline. A naturally shy cat hiding in a familiar spot during a loud event is different from a normally social cat suddenly avoiding people and staying in one spot for most of the day. If you're unsure, a call to your vet's office to describe the change is a reasonable next step.
Is it normal for cats to throw up hairballs sometimes? Occasional hairballs can be normal, but frequent vomiting (more than once every week or two), or vomiting combined with weight loss or appetite changes, is not something to assume is "just hairballs" — it's worth a vet visit.
Veterinary disclaimer: This article is for general educational purposes only and is not a substitute for professional veterinary diagnosis, examination, or treatment. It cannot tell you what's wrong with your specific cat. If your cat is showing any of the urgent signs listed above, contact an emergency veterinarian immediately rather than relying on this or any other article.
Sources
- Texas A&M College of Veterinary Medicine — When Is Your Cat Hiding Illness or Injury?
- Texas A&M College of Veterinary Medicine — Recognizing a Pet Emergency
- ASPCA — Animal Poison Control Center
Sources verified during editorial review, September 2026.