Urine odor may be certain physiological phenomena, but also may be the manifestation of certain diseases symptoms, such as cystitis, diabetic ketoacidosis, etc., should be timely consultation to identify the cause of the disease. 1. Physiological factors: May be too much protein food intake, so that the ammonia in the urine to increase the production of substances, so there is an increase in odor; may also be urine in the bladder storage time is too long, drinking too little water has a relationship, coupled with the weak reabsorption function of the bladder mucosa, so that the concentration of urine aggravated, the emergence of the increase in odor. 2. Pathologic factors: (1) cystitis, generally belonging to bacterial infection, bacteria in the urinary tract rapid mass reproduction will produce a large number of metabolites, urine is easy to become turbid, and the sensation of tartness and odor is obvious, and even some patients’ urine can be foul-smelling. (2) Diabetic ketoacidosis, is a serious metabolic disorder syndrome. Due to impaired glucose utilization, increased fat decomposition will lead to an increase in ketone bodies, and ultimately converted to acetone from the urine, and acetone itself is characterized by the presence of such an odor as rotten apple flavor, so the urine can appear rotten apple flavor. This symptom alone is not enough to diagnose the disease, it may also be caused by other factors, such as phenylketonuria. It is recommended that if physiological causes are ruled out, timely consultation should be made with a doctor to clarify the cause of the disease and give targeted treatment.