The discharge of milky liquid when urinating may be caused by prostatitis, purulent urethritis, celiac disease and other diseases, the patient should consult a doctor in time to clarify the cause of the disease. 1. Prostatitis: Prostatitis is a prostate disease caused by a variety of complex causes, with urethral irritation and chronic pelvic pain as the main clinical manifestations, usually manifested in frequent urination, urinary urgency, urinary pain, perineal discomfort, at the same time, the patient may also have the symptom of milky fluid discharge when urinating. 2. purulent urethritis: urethritis is likely to be gonococcal or non-gonococcal infections, usually through sexual contact with the infection, purulent urethritis patients will also appear to have milky white fluid in the urine, such patients will also have frequent urination, urinary pain, urethral tingling and other symptoms. 3. Celiac Disease: The discharge of milky fluid when urinating may also be caused by celiac disease, celiac disease is often celiac fluid or lymphatic fluid mixed in the urine, resulting in a milky appearance of the urine, the urine contains lymph, fat, celiac particles, protein and other substances. It may be caused by parasitic infection, inflammation and other factors. When milky-white fluid is discharged while urinating, you should seek medical attention and active treatment.