Common Cat Symptoms and What They Mean

Cats are solitary hunters by nature, and seeking out quiet, enclosed spaces is normal feline behavior to some extent. However, a noticeable increase in hiding—especially in a cat that is typically social and interactive—is one of the most reliable early indicators that something is wrong. Cats are evolutionarily programmed to conceal vulnerability, which means that hiding is often the first sign of pain, illness, or significant stress, appearing before more obvious symptoms like appetite loss or vomiting.

Medical causes of increased hiding include pain from any source (dental disease, arthritis, urinary tract disease, abdominal discomfort), nausea, fever, and systemic illness such as kidney disease or cancer. Cats with upper respiratory infections may hide because they feel congested and vulnerable. A cat that suddenly starts hiding under beds, in closets, or behind furniture and resists being coaxed out should be evaluated by a veterinarian, particularly if the behavior change persists for more than 24 to 48 hours or is accompanied by other symptoms.

Environmental and psychological factors can also trigger hiding. A new pet, a new baby, construction noise, a move to a new home, or conflict with another household cat can all cause a sensitive cat to withdraw. In multi-cat households, one cat may bully another, causing the victim to hide to avoid confrontation. If you've ruled out medical causes with your veterinarian, addressing the environmental trigger—providing additional vertical space, separate resources for each cat, and pheromone diffusers like Feliway—can help restore your cat's confidence.

Litter box avoidance is one of the most common reasons cats are surrendered to shelters, yet it is almost always caused by an underlying medical condition rather than behavioral defiance. The most frequent medical cause is feline lower urinary tract disease (FLUTD), an umbrella term that includes bladder inflammation (feline idiopathic cystitis), urinary tract infections, bladder stones, and urethral blockages. Cats with FLUTD associate the litter box with pain and begin eliminating elsewhere. Male cats straining to urinate may have a life-threatening urethral obstruction requiring emergency care.

Other medical causes include arthritis (the cat finds it painful to climb into a high-sided box), diabetes or kidney disease (increased urine volume makes the box feel dirty faster), gastrointestinal issues causing urgent defecation, and cognitive dysfunction in senior cats. A thorough veterinary exam with urinalysis is the essential first step whenever a cat breaks litter box habits. Treating the medical issue almost always resolves the behavior.

If medical causes are ruled out, the issue may be environmental. Cats are fastidious about their elimination areas and may reject a box that is too dirty, too small, located in a noisy or high-traffic area, or filled with a litter substrate they dislike. The general guideline is to provide one litter box per cat plus one extra, scooped at least daily, with unscented clumping litter in uncovered boxes placed in quiet, accessible locations. Avoid placing boxes near food and water bowls or noisy appliances. When introducing changes to the litter setup, do so gradually to avoid additional stress.

Many cat owners accept occasional vomiting as normal, but veterinary consensus is clear: vomiting more than once per week is not normal and warrants investigation. Occasional hairball vomiting (once every few weeks) can be within the range of normal for long-haired cats, but frequent hairballs may indicate an underlying gastrointestinal motility issue or excessive grooming from skin disease or stress. True vomiting should be distinguished from regurgitation—vomiting involves active abdominal contractions, while regurgitation is a passive process where food comes back up undigested shortly after eating.

Common medical causes of vomiting in cats include inflammatory bowel disease (IBD), food allergies or intolerances, pancreatitis, intestinal parasites, hyperthyroidism, and kidney disease. Foreign body ingestion is also a significant concern, especially in younger cats that may swallow string, ribbon, hair ties, or small toys. Linear foreign bodies (string, yarn, tinsel) are particularly dangerous because they can saw through intestinal walls and cause peritonitis, a life-threatening abdominal infection requiring emergency surgery.

Your veterinarian's diagnostic approach will typically begin with bloodwork (including thyroid levels in cats over seven years old), urinalysis, and fecal testing. Abdominal X-rays or ultrasound may be recommended to look for foreign bodies, masses, or intestinal thickening. In some cases, an endoscopy or surgical biopsy may be needed to differentiate IBD from intestinal lymphoma, which can appear very similar on imaging. Treatment depends entirely on the underlying cause, so a thorough diagnostic workup is essential rather than simply managing symptoms with anti-nausea medications.

Unexplained weight loss in cats is always a significant finding that demands veterinary attention. Because cats are relatively small animals, a loss of even half a pound can represent a meaningful percentage of their body weight. Pet owners often miss gradual weight loss because they see their cat daily; this is one reason why regular veterinary weigh-ins (at least twice yearly) are so valuable. Running your hands along your cat's spine and ribs can help you detect changes—if the bones feel more prominent than before, your cat may be losing muscle mass and body condition.

The most common causes of weight loss in cats over seven years of age are hyperthyroidism, diabetes mellitus, chronic kidney disease, and cancer (particularly intestinal lymphoma). Hyperthyroid cats classically eat ravenously while still losing weight, and may also exhibit increased thirst, hyperactivity, vomiting, and a rapid heart rate. Diabetic cats similarly show increased appetite, increased water consumption, and increased urination. Kidney disease tends to cause gradual weight loss with decreased appetite, increased water intake, and eventually nausea and poor coat quality.

In younger cats, weight loss may be caused by intestinal parasites, inflammatory bowel disease, dental disease that makes eating painful, or chronic infections like feline immunodeficiency virus (FIV) or feline leukemia virus (FeLV). Your veterinarian will typically start with a comprehensive blood panel, urinalysis, and thyroid level measurement. Based on initial results, additional diagnostics like abdominal ultrasound, chest X-rays, or specialized hormone testing may be recommended. Early detection and treatment of the underlying condition often significantly improves outcomes and quality of life.

Appetite loss in cats is more medically urgent than in dogs because of a condition called hepatic lipidosis (fatty liver disease). When a cat stops eating, the body begins mobilizing fat stores for energy, and the liver can become overwhelmed by the influx of fat, leading to liver failure. This process can begin within as few as 48 to 72 hours of complete food refusal, and overweight cats are at particularly high risk. Hepatic lipidosis is treatable if caught early (usually with aggressive nutritional support via feeding tube), but can be fatal if the diagnosis is delayed.

The most common medical causes of appetite loss in cats include upper respiratory infections (a congested cat can't smell food and won't eat), dental disease, nausea from kidney disease or pancreatitis, stress, and pain. Cats are also highly sensitive to food changes—switching brands, flavors, or even the shape of kibble can cause a cat to refuse food. Similarly, cats may reject food if their feeding station has been moved, if a new pet is eating nearby, or if they associate their food bowl with an unpleasant experience (being given medication, for example).

If your cat hasn't eaten in more than 24 hours, try offering a small amount of a highly palatable food such as warmed canned tuna (in water, not oil), meat-flavored baby food (without onion or garlic), or a veterinary recovery diet. If the cat still refuses by the 48-hour mark, veterinary intervention is necessary. Your vet will assess for underlying disease and may administer anti-nausea medication (maropitant or ondansetron), appetite stimulants (mirtazapine), and subcutaneous fluids to address dehydration. Do not wait longer than 48 hours, especially with an overweight cat, as the risk of hepatic lipidosis increases with every day of fasting.