Why Is My Cat Breathing Through Its Mouth and Not Eating?

1 Overview

1. Heatstroke

Cats regulate temperature poorly, so they dislike both cold and heat. In summer, high indoor temperatures or taking a cat out in the heat can cause heatstroke, whose main signs are lethargy, reduced appetite, a dry nose, and open-mouth panting.

If temperatures have been high lately and your cat is panting with no appetite, watch the room temperature — keep it around 25°C, offer more water, and give a pet electrolyte solution for energy. But do not blast cold air conditioning suddenly, as the temperature swing or long exposure can easily cause a cold.

2. Pneumonia and pulmonary edema

Mouth breathing with lost appetite may relate to respiratory disease. Check for a runny nose or increased eye discharge; if present, suspect feline rhinotracheitis virus first.

Some subtler signs may come from feline asthma, pneumonia, or pulmonary edema. These progress less acutely than rhinotracheitis but can be harder to treat, so a veterinary check is advised.

3. Heart disease

Dilated cardiomyopathy and hypertrophic cardiomyopathy are common feline heart diseases; in young cats, also consider congenital heart disease.

A shared feature of most heart disease is impaired circulation, causing pulmonary edema or pleural effusion, which leads to labored, open-mouth breathing.

If your cat is often lethargic, lies still, tires quickly from play, or shows breathing difficulty, seek veterinary heart checks promptly.

4. Oral disease

Oral disease — ulcers, gingivitis, and the like — commonly causes lost appetite and mouth breathing. Pain keeps the mouth from closing, causing drooling and painful cries while chewing, then refusal to eat.

This needs veterinary anti-inflammatory and oral-spray treatment, with fluid therapy when the cat cannot eat. If a clinic is not immediately available, metronidazole tablets and an oral antiseptic spray can help, and maintain daily oral hygiene with brushing or a pet oral rinse.

The causes above are only common possibilities. If you cannot judge the cause yourself, take the cat to a veterinary clinic or consult an online veterinarian promptly.