From sudden appetite loss to chronic conditions like diabetes — the symptoms that matter and when they need a vet's attention.
Cats tend to hide illness, so the signs in this section are often small: eating a bit less, drinking more, hiding, or a change in litter box habits. Each guide explains what a sign can point to and how fast it needs a vet. The main references are the Cornell Feline Health Center and the Merck Veterinary Manual.
Two situations can't wait. A cat, especially a male, that keeps straining in the litter box and passes little or no urine may have a urethral blockage, which Cornell calls an absolute emergency. And a cat that stops eating is at risk of hepatic lipidosis, a serious liver condition that Cornell says is almost always accompanied or preceded by loss of appetite. Cornell advises calling the vet if a cat with a normal appetite refuses food even for a day.
For a cat that has gone off its food, start with why is my cat not eating?. For vomiting, read why is my cat vomiting?, and for litter box trouble, urinary tract infections in cats. Middle-aged and older cats get their own guides on hyperthyroidism and diabetes, two conditions worth knowing about before the senior years.
Cats rarely pant, so it's natural to worry when yours does in summer. Here's when it's mild heat stress and when panting means an emergency vet visit.
Weight loss despite a big appetite could mean hyperthyroidism, the most common endocrine disease in older cats. Learn the symptoms, causes, and treatments.
Excessive thirst and weight loss in cats can signal diabetes. Learn the symptoms, causes, and treatment options, including diet and insulin therapy.
Straining to urinate or accidents outside the box can signal a urinary infection in cats. Learn the symptoms, causes, treatment, and emergency warning signs.
Occasional cat vomiting can be normal, but frequent vomiting often signals a health issue. Learn the common causes, hairball vs. illness, and when to see a vet.
A cat that stops eating can be a serious warning sign. Learn the causes of appetite loss in cats, tips to encourage eating, and when it's an emergency.
Every guide in this section is shaped by one fact: cats are both predator and prey, and visible weakness is dangerous for prey. A cat in genuine discomfort will often keep eating, keep using the litter box and keep looking approximately normal for far longer than a dog in the same state. By the time something is obvious, it has usually been developing for a while.
This shifts what owners should be watching. The early signals are changes in pattern rather than dramatic symptoms: sleeping somewhere new, a drop in grooming so the coat looks slightly unkempt, hesitating before jumping onto a surface they always used, or drinking noticeably more. Any of those persisting beyond a few days is worth a call, even with no other symptom.
In a dog, skipping a day of food is usually unremarkable. In a cat it is not. When a cat stops taking in calories, body fat mobilises to the liver faster than the liver can process it, and hepatic lipidosis — fatty liver disease — can develop within a few days. It is life-threatening, and overweight cats are at the highest risk.
The practical rule is much tighter than most owners realize: a cat that has eaten nothing for twenty-four hours needs veterinary attention, not another day of waiting to see whether appetite returns. That clock applies regardless of the underlying cause, including when the cause is a diet.
Hyperthyroidism, diabetes and chronic kidney disease account for a large share of illness in cats past about eight, and they share an unhelpful trait: the early signs read as ordinary. Drinking more. Eating well but losing weight. Slightly more vocal at night.
A cat that is eating enthusiastically while getting thinner is the pattern most worth acting on — it is close to a textbook presentation of hyperthyroidism, and it looks from the outside like a cat doing fine. All three are far more manageable when caught early, which is the entire argument for annual bloodwork in cats over seven, before anything appears wrong.
A male cat straining in the litter box without producing urine is a genuine emergency and needs a vet immediately, at whatever hour it is. Urinary blockage is far more common in males because of the narrower urethra, and it becomes fatal within roughly twenty-four to forty-eight hours through kidney failure and cardiac arrest.
It is frequently mistaken for constipation, because the posture is identical — a cat crouching in the tray, straining, producing nothing. If you are unsure which you are looking at, treat it as the blockage. That is the error with a survivable outcome.
