What causes a dog’s mouth to stink?

The causes of bad breath in dogs are: firstly, long term non-brushing, oral problems caused by tartar or oral bacteria breeding. Secondly, indigestion, such as eating too much and too mixed. Thirdly, caused by fire. Bad breath can be improved by brushing your dog’s teeth regularly or by adjusting the structure of his diet. For example, a lighter diet, not too much food at once. Vitamin supplements can also be appropriate.