Many owners complain that their cats have bad breath and don't know why. Just as humans don't have bad breath because they keep their mouths clean and healthy, cats are the same. When owners find that their cats have severe bad breath, it may be caused by oral diseases. 
I. Methods for checking a cat's bad breath
1. Does your cat drool? If so, it may be due to an oral infection or gum disease, especially in cats that are teething. Discolored old teeth (not white) that cannot fall out on their own can also cause bad breath, and you need to have the old teeth extracted by a veterinarian.
2. Are the cat's teeth dirty? If so, the reason is tartar.
3. Do you have mouth ulcers? It could be a mouth infection.
4. Is your cat vomiting? It might have a stomach problem.
5. Is the cat having spasms? It could be a vitamin deficiency.
In other words, the following factors can cause bad breath: oral infections, tooth decay, ulcers, indigestion, and vitamin B deficiency.
Treatment for bad breath in cats: Take your cat to a trusted veterinarian at a suitable time for diagnosis, learn about the cat's true health condition from the veterinarian, and follow the veterinarian's treatment instructions. 
II. Causes of Bad Breath in Cats
1. Dental plaque (tartar)
To help it develop a good brushing habit, find an assistant. Gently lift the cat's upper lip upwards with your index finger and thumb (the assistant's palm is above the cat's head, and the pressure should be appropriate; of course, their other hand should hold the cat properly). Place your index finger into the cat's lower incisors and gently press down on the jaw. Use a children's toothbrush soaked in diluted salt water to clean the cat once a week.
2. Oral ulcers
It could be an oral infection. Frequently feeding cats soft or canned food can easily lead to tooth decay. These foods cause plaque to build up around the cat's teeth, which can lead to gingivitis. Bacteria can then enter the alveolar bone and cause periodontal disease. The result is loose teeth and necrosis of the dental nerve, at which point extraction is necessary.
3. The food you eat has a strong odor.
For example, after eating strongly flavored meats or fish, the smell lingers for a long time.
4. Indigestion
If your cat has mild indigestion, you can feed it small, frequent meals of fresh, high-quality cat food. Human antacids may be effective (of course, only after diagnosis and with the approval of a veterinarian).
5. Both constipation and diarrhea can cause bad breath.
This could be a vitamin deficiency. There are many types of B vitamins, all of which are essential for cats. Feeding too much processed food can lead to vitamin B1 deficiency, with symptoms including seizures and strokes. Excessive food processing can destroy vitamin B6, resulting in weight loss, anemia, and seizures. Vitamin B complex injections, yeast tablets, and multivitamin B supplements can treat vitamin B deficiency. Treatment for bad breath in cats requires a diagnosis by a veterinarian, followed by treatment according to the veterinarian's recommendations.
Pet owners should take the issue of bad breath in cats seriously. The most important thing is to clean your cat's mouth regularly to prevent problems, such as brushing their teeth. If your cat does get an oral disease, it should be treated promptly.
