The causes of foul odor in the mouth need to be considered as salivary gland inflammation, dental disease, periodontal disease as well as stomach disease and Helicobacter pylori infection. A few people may have liver odor due to serious liver disease, and manual examination of teeth, salivary gland ultrasound, liver function and gastroscopy should be done before treatment. If it is periodontal abscess, it can be coated with iodine glycerin, incision and drainage if necessary, caries with tooth bleeding, it can be treated by filling or inlay after tooth extraction, and scaling can be done when there is dental calculus. If it is caused by gastritis, you can use lactase raw and stomachic tablets to help digestion, together with omeprazole, thioglycollate and other drugs to promote the recovery of gastritis and gastric ulcer. In case of serious liver disease with liver odor, it mostly indicates that the liver has reached the stage of liver failure and mostly requires hospitalization with medications such as monosodium glutamate, arginine, branched-chain amino acids and albumin.