The cause of the unpleasant odor from the body may be bad breath, halitosis, diabetic ketoacidosis, ammonia metabolism disorders. 1. Bad breath: abnormal secretion of sweat glands at the top of the armpit, the secretion increases and is rich in protein, due to poor ventilation of the armpit can not evaporate in time, resulting in a large number of bacterial growth, decomposition of secretion of sweat glands at the top of the armpit, resulting in a bad smell. 2. Bad breath: dental caries and periodontal infection are bacterial infection related diseases, bacteria can decompose food residue in the mouth and produce odor. In addition, the cause of bad breath is also related to the neighboring tissues and organs, such as rhinitis, as well as systemic diseases, the more typical is diabetes and digestive diseases, there will be some special odor, through the digestive tract through the oral cavity to reflect. 3. Diabetic ketoacidosis: diabetic patients with high blood glucose, the body with sugar disorder, resulting in patients with ketone body generation, and acetone, β-hydroxybutyric acid, acetoacetic acid, collectively referred to as ketone bodies, acetone has a rotten apple flavor, so diabetic ketoacidosis patients exhale will have rotten apple odor. 4. Disorders of ammonia metabolism: the synthesis of urea in the liver is the only way of ammonia metabolism, and patients with severe viral hepatitis, severe cirrhosis, severe fatty liver disease and other severe liver diseases may have ammonia metabolism disorders, so that the blood ammonia level is too high, and ammonia has a smell similar to rotten eggs, so ammonia odor may occur. If the patient’s body emits an unpleasant odor, it is recommended to go to the hospital, under the guidance of the doctor, to identify the cause, and then carry out symptomatic treatment for the cause.