The taste of urine in the mouth is a manifestation of aggravated halitosis, and the common causes are: diabetic ketoacidosis, renal insufficiency, and dental lesions. 1. Diabetic ketoacidosis: can cause the patient’s body carbohydrates can not be effectively decomposed to provide energy, so the body will be a large number of decomposition of fat, which produces an increase in metabolic products ketones, rotten apple flavor, sometimes the patient can not accurately distinguish, may feel like the taste of urine. 2. renal insufficiency: can affect the patient’s detoxification function, resulting in some of the toxins retained in the body, and toxins have urea components, in the oral cavity retained for too long, will be decomposed into ammonia, resulting in the taste of urine. Uremia patients feel that the taste of urine in the mouth will be more serious. 3. Dental lesions: for example, inflammation around the teeth, dental caries, etc., will also lead to a bad taste in the mouth, the patient may think it is the smell of urine. All in all, if there is a smell of urine in the mouth, it is recommended to consult a doctor in time and pay attention to the cleanliness of the mouth in daily life.