Cats hide illness well. Changes in routine often speak first.
This guide helps cat owners identify meaningful changes in their cat's everyday patterns and understand when those changes need prompt veterinary attention.
Not eating or drinking changes
How urgently to respond to a cat that's eating less depends on several things: whether they're refusing food entirely or just eating less, their age, any known health conditions, whether other symptoms are present (vomiting, lethargy, apparent pain), and how suddenly the change came on. A senior cat or a cat with a known health condition who skips a meal warrants earlier contact with your vet than a healthy adult who ate less once. When in doubt, call your vet — they can help you decide how quickly to act.
Hydration matters just as much. Cats have a naturally low thirst drive and often rely on moisture from wet food. Watch for a sudden increase in drinking, which can signal kidney changes, diabetes, or thyroid issues. A cat drinking far less than usual — or refusing water entirely — also warrants attention.
Emergency signs — act immediately
Some symptoms require same-day or emergency veterinary care. Do not wait to monitor these situations at home:
- Difficulty breathing, open-mouth breathing, or labored breathing
- A cat straining to urinate with little or no result — contact a veterinarian or emergency clinic immediately, especially male cats. A urinary blockage can become fatal within hours if untreated.
- Collapse or sudden inability to walk normally
- Seizures or uncontrolled muscle movements
- Pale, white, blue, or yellow gums
- Suspected ingestion of a toxic substance
- Severe or persistent vomiting or diarrhea with blood
- Signs of extreme pain — crying, guarding, inability to settle
For non-emergency concerns that persist — such as reduced appetite, subtle lethargy, or litter box changes — contact your vet for guidance. Early assessment is almost always better than waiting.
Vomiting, diarrhea, and hairball patterns
Occasional vomiting is common in cats, but not every episode is harmless or simply a hairball. Frequent vomiting, bile, blood, or vomiting that occurs alongside other symptoms — lethargy, weight loss, or appetite changes — should be evaluated by a vet.
Hairballs are often assumed to be routine, but frequent hairball-related vomiting can point to over-grooming caused by stress, skin irritation, or anxiety. It is not always safe to dismiss repeated episodes as normal. If your cat is producing hairballs several times a week, this is worth discussing with your vet.
Diarrhea lasting more than 24 hours, or diarrhea that contains blood or mucus, needs prompt veterinary attention. Short episodes after a food change are more common, but ongoing digestive issues can lead to dehydration and may signal inflammatory bowel disease, parasites, or food intolerance.
Track frequency and appearance when you can — this information helps your vet assess what is happening more quickly.
Litter box changes
The litter box is one of the clearest windows into a cat's health. Changes in urination patterns — going more frequently, producing very little each time, urinating outside the box, or straining — can signal a urinary tract issue or, in male cats, a potentially life-threatening blockage.
Accidents near the litter box, crying or vocalizing while using it, or avoiding it entirely are all signs of discomfort. Cats rarely stop using a clean litter box for behavioral reasons alone — physical discomfort or illness is often the underlying cause.
Watch for blood in urine, very dark or cloudy urine, or unusually strong odor. Any significant change in litter box habits — including stool consistency, frequency, or location — is worth monitoring and discussing with your vet if it persists.
Weight loss, grooming less, hiding, lethargy, and dental signs
Gradual weight loss in cats is easy to miss, especially with longer-coated breeds. Run your hands along your cat's ribs monthly — if you can feel them easily without pressing, or if the spine and hip bones become prominent, weight loss may be occurring. Unexplained weight loss is always a reason to consult your vet.
Cats are meticulous groomers. A coat that becomes dull, matted, or unkempt — or a cat that stops grooming areas it normally would — can indicate pain, arthritis, dental discomfort, or systemic illness. Over-grooming that leads to bald patches also warrants attention, as it often reflects stress or a skin condition.
Hiding more than usual, reluctance to interact, or a general withdrawal from activity are quiet signals that something may be off. Cats instinctively conceal discomfort, so these behavioral shifts can be an early indicator before more obvious symptoms appear.
Lethargy — less play, less movement, or spending far more time sleeping than usual — is different from a cat that is simply relaxed. If your cat shows noticeably reduced energy over several days, this should be evaluated.
Dental health is often overlooked. Bad breath, drooling, pawing at the mouth, dropping food, or reluctance to chew can all signal dental pain or gum disease. Dental issues are painful and can affect appetite and overall health.
Keep your pet's health in one place
Log symptoms, track medications, and store vet visit notes so nothing important gets forgotten.