To treat bad breath in cats, feed them a bland diet and provide plenty of drinking water. Then, analyze the cause of the bad breath, such as uneaten food, oral diseases, or digestive system problems, and consult a veterinarian for appropriate treatment. If the bad breath is caused by oral ulcers, supplementing with vitamin B may be necessary to improve the resistance of the oral mucosa. If the cat's urination and defecation are abnormal, consider digestive system issues; you can feed them appropriate amounts of probiotics to regulate the intestinal environment. 
Solutions for bad breath in cats:
First, address the cat's diet. Unsuitable food or indigestion can cause stomach upset and bad breath. In this case, changing the cat's food and giving them a gut-regulating supplement is recommended. Secondly, bad breath can be caused by oral diseases such as stomatitis, gingivitis, periodontitis, angular cheilitis, glossitis, and tartar buildup. These are the most common causes of bad breath in cats.
