The causes of smelly urine are purulent infections of the urinary tract, such as urethritis, acute cystitis, pyelonephritis, renal abscess, renal tuberculosis and other diseases, because urine contains a lot of pus cells and bacterial metabolism products leading to smelly urine, and there will also be frequent urination, urgency, urinary pain, hematuria and other bladder irritation, which need to be diagnosed by urine routine and urine culture tests. It is also related to personal dietary habits. For example, after eating high-calorie, high-sugar and meat foods, can lead to increased protein content in the urine, when a small amount of bacteria in the urine break down the protein will cause the urine to smell. Men with phimosis or circumcision, there are a lot of local secretions and foreskin scale, and combined with bacterial infection will also have a fishy odor when urinating.