A cat that grunts when breathing is producing a sound that usually originates from a partial obstruction somewhere in the upper airway, most often in the nose, the back of the throat, or the voice box. The medical term for this harsh, snoring-like sound is stertor, and it signals that air isn’t flowing freely. While some cats grunt occasionally due to their facial structure or temporary congestion, persistent or worsening grunting points to a problem that needs veterinary attention.
What the Grunting Sound Actually Means
Grunting during breathing is distinct from other respiratory noises your cat might make. A low, rough sound that happens as your cat breathes in is typically stertor, caused by turbulent airflow through a narrowed upper airway. Cats that make this sound while awake almost always snore when they sleep, too. This is different from wheezing, which is a higher-pitched, musical sound that comes from the lower airways (the lungs and bronchial tubes) and tends to happen on the exhale.
A third type of sound, stridor, is a harsh, high-pitched noise heard during inhalation that points to a problem specifically at the voice box. It’s much less common in cats than stertor. Identifying which sound your cat is making helps narrow down where the obstruction sits, so pay attention to when the noise happens (breathing in versus out) and whether it’s low or high-pitched.
Nasopharyngeal Polyps
One of the most common causes of grunting in cats, especially younger ones, is a nasopharyngeal polyp. These are benign growths that develop on a slender stalk in the back of the throat or inside the ear canal, then slowly extend into the airway over a period of months. As the polyp grows, it gradually blocks the nasal passage, and the cat essentially feels like something is stuck above its palate. When it tries to breathe through its nose, the air has to squeeze past the obstruction, producing that grunting or snoring noise.
Polyps often come with other signs: nasal discharge, sneezing, head shaking, difficulty swallowing, and sometimes a startling honking noise called reverse sneezing where the cat seems to be desperately trying to clear its throat. Polyps can grow on both sides and, if large enough, may interfere with drainage from the nose entirely. The good news is that these growths are not cancerous. They’re typically removed with a relatively straightforward procedure, though there’s a chance of regrowth.
Flat-Faced Breeds and Airway Anatomy
If your cat is a Persian, Himalayan, Exotic Shorthair, or any mix with a noticeably flat face, the grunting may be built into their anatomy. Flat-faced (brachycephalic) cats have several structural features that make breathing noisier: narrowed nostrils, an undersized nasal chamber, compressed structures inside the nose, and a soft palate that’s too long for the shortened skull. All of these increase airway turbulence and resistance, forcing air through tighter spaces and creating audible breathing sounds even at rest.
Research comparing brachycephalic cats to cats with standard facial proportions confirms that breeds like Persians and Exotics are significantly more likely to have breathing difficulties and substantial breathing noise. Some degree of grunting in these breeds is expected, but it shouldn’t be severe, and it shouldn’t get worse over time. If a flat-faced cat that previously breathed quietly starts grunting louder, something else is going on.
Excess Weight and Breathing
Overweight and obese cats often breathe more noisily, and the reason is mechanical. Fat deposits in the chest and abdominal cavity physically limit how far the diaphragm can move, increase pressure inside the chest, and reduce the flexibility of the entire respiratory system. The result is shallower, faster breaths that require more effort. This extra effort can produce grunting, especially when the cat lies in certain positions or after minimal activity.
For cats that are both overweight and flat-faced, these effects compound. An already narrow airway becomes even harder to breathe through when the respiratory muscles are working against extra body mass. Weight loss alone can meaningfully reduce breathing noise in these cats.
Upper Respiratory Infections and Inflammation
A cat with a cold or upper respiratory infection can develop temporary grunting. Swelling of the tissue inside the nasal passages, combined with mucus buildup, narrows the airway enough to cause audible breathing. This is similar to how you might snore or breathe loudly when you’re congested. In most cases, the grunting resolves as the infection clears, typically within one to three weeks.
Chronic infections or ongoing inflammation from allergies can cause long-term swelling of the nasal structures, leading to persistent noisy breathing even when the cat otherwise seems healthy. Narrowing of the nasopharynx (the passage connecting the nose to the throat) from scarring after repeated infections is another possibility, and this type of narrowing tends to be permanent without intervention.
Less Common Causes
Tumors in the nasal cavity or throat can obstruct airflow in much the same way as polyps, but they tend to occur in older cats and may be accompanied by bloody nasal discharge or facial swelling. Laryngeal disease, where the voice box doesn’t open properly, is rare in cats but can produce harsh breathing sounds along with difficulty swallowing. Foreign objects lodged in the nose or throat are uncommon but possible, particularly in outdoor cats.
Feline asthma is worth mentioning because owners sometimes confuse it with upper airway grunting. Asthma primarily causes coughing and wheezing rather than grunting, and the breathing effort is most visible in the abdomen, which pumps noticeably as the cat pushes air out. The breaths are shallow and rapid. Asthma is a lower airway problem, so the sound and the pattern look different from the snoring-type noise of an upper airway obstruction.
How to Monitor Your Cat at Home
A healthy resting cat takes between 16 and 40 breaths per minute. You can count this by watching your cat’s chest or belly rise and fall while it’s relaxed or sleeping. Counting for 15 seconds and multiplying by four gives a quick estimate. If the rate consistently sits above 40 at rest, or if you notice it climbing over days or weeks, that’s meaningful information to share with your vet.
Beyond counting breaths, watch for changes in the quality of breathing. Note whether the grunting happens only during sleep, during activity, or all the time. Record whether it started suddenly or crept in gradually. Pay attention to whether your cat is also sneezing, coughing, eating less, or showing nasal discharge. Even a short video clip of the breathing sound on your phone can be enormously useful at a vet appointment, since cats have a talent for acting perfectly normal in the exam room.
Signs That Need Urgent Attention
Some breathing patterns indicate that a cat is in genuine distress. Open-mouth breathing in a cat that isn’t overheated or stressed is always abnormal and often an emergency. Other urgent signs include: a head held low with the neck extended forward, visible effort from the abdominal muscles to push air in or out, panting, frequent coughing, gagging as though about to vomit, and any bluish tint to the gums or tongue. A cat showing these signs needs veterinary care immediately, not at the next available appointment.
What Happens at the Vet
The diagnostic process for noisy breathing typically starts with a physical exam, including a look inside the mouth and throat. Your vet will listen to the lungs and try to localize where the abnormal sound is coming from. X-rays of the neck and chest are a common next step, useful for spotting masses, fluid, or structural collapse. If the cause isn’t clear from initial tests, more advanced imaging like a CT scan or a scope passed into the nasal passages or airway may be needed, usually under sedation.
Treatment depends entirely on what’s found. Polyps are physically removed. Infections are treated with appropriate medications. Narrowed nostrils in brachycephalic cats can sometimes be surgically widened. For overweight cats, a structured weight loss plan may be the single most effective intervention. In many cases, identifying and addressing the underlying cause resolves the grunting entirely or reduces it to a level that doesn’t affect the cat’s quality of life.