The discharge on the man’s underwear may be prostate fluid, or it may be urethral drip caused by prostatitis, and it may be caused by urethritis. 1. Physiological factors: If there is a white discharge on the man’s underwear, the amount is relatively small, may be the prostate fluid, this is generally a normal phenomenon, do not need to worry too much. 2. Prostatitis: prostatitis can also lead to discharge on the man’s underwear, in this case the discharge is white or yellow purulent secretion, the patient may also appear urinary frequency, urinary urgency, painful urination, intermittent urinary line, suprapubic pain and other symptoms. 3. Urethritis: Urethritis can also lead to discharge on the man’s underwear, in this case the discharge is also yellow sticky purulent discharge, the patient can also appear frequent urination, urinary urgency, painful urination, urethral orifice red and swollen and other symptoms. After eliminating physiological factors, if symptoms such as discharge from men’s underwear continue unabated, it is recommended to consult a doctor in time to identify the cause and ask the doctor to dispose of it.