Published by: Ingrid King. Last Updated on: June 26, 2023 by Crystal Uys


Cats are masters at hiding signs of illness. This is a throwback to their wild origins: in the wild, a sick animal easily becomes prey. Because of this, it’s up to cat parents to know what to look for. Any changes in your cat’s normal routine, behavior and attitude could be the first indicator that something is wrong.

Cat parents often don’t realize that problems can develop slowly and cats don’t show symptoms until a disease is already advanced. Early detection is important: there’s a much better chance that the problem can be treated successfully, and you’ll also save yourself money by avoiding costly veterinary fees for treating an advanced illness.

The 10 signs that may be cause for concern

1. Decreased energy or activity level

If your cat suddenly refuses to engage in normal play behavior or seems lethargic, this could be a sign that she’s not feeling well.

devon rex kitten with beautiful eyes resting on cat tree
Image Credit: Veera, Shutterstock

2. Changes in appetite

If your cat suddenly starts eating voraciously, or refuses to eat, it can be an indicator of a serious problem.  Complete anorexia (not eating) is especially dangerous in cats and can lead to hepatic lipidosis, a potentially life threatening form of liver disease, within 24-48 hours.

3. Increased thirst and/or urination

Increased water intake can be a sign of kidney disease or diabetes. An increase in the amount of urine output, or an increase in the frequency of urination, can be a sign of urinary tract disease.

4. Changes in behavior

If your cat starts to hide, refuses to play, or becomes aggressive for no apparent reason, these changes may be caused by a physical problem.

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5. Vomiting and/or diarrhea

While a single bout of vomiting or diarrhea may not be cause for concern, ongoing vomiting and diarrhea can be sign of a serious gastro-intestinal problem.

6. Inappropriate elimination

If your cat all of a sudden refuses to use the litter box, ruling out a medical issue should always be your first step.

7. Weight loss or weight gain

Sudden weight loss or weight gain is always a cause for concern and requires veterinary attention.

Sick and skinny cat sitting on the pavement
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8. Poor hair coat, hair loss or excessive scratching or grooming

Poor hair coat can be caused by any number of conditions. Excessive scratching and grooming may be caused by allergies or parasites.

9. Foul odor

A foul odor coming from your cat’s mouth, ears or skin may be the indicator of dental disease, infection, or other problem.

10. Abnormal vocalizations

If your cat starts to vocalize in ways that are not normal for her, this can be a cause for concern.

Don’t dismiss any subtle change to your cat’s normal pattern. Schedule an exam with your cat’s veterinarian at your earliest convenience if you notice any of these signs.

abbyssinian cat meowing
Image Credit: New Africa, Shutterstock

FTC Disclosure: This post was sponsored by PDSA, also known as the People’s Dispensary for Sick Animals, a well-liked animal charity based across the United Kingdom. Regardless of payment received, you will only see topics on this site that I believe are of interest to my readers. This post was first published in 2014 and has been updated.

Featured Image Credit: Pixabay

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