Frequent urination at night is not a reflection of one disease, but a symptom of many diseases, and is defined as urinating more than three times at night. The causes of frequent urination at night include prostatitis, prostate enlargement, urethritis, cystitis, diabetes, etc. Urethritis is one of the diseases that cause frequent urination at night because it is caused by pathogens such as bacteria attacking the epithelial cells of the urinary tract. At night when the body is asleep, this stimulation will be more intense, so there will be more frequent urination than during the day, and it will also be accompanied by painful urination, urgency and incomplete urination. If the bladder is inflamed, it will keep stimulating the bladder wall, and this signal will be transmitted to the brain control center, and there will be a constant urge to urinate, and thus the phenomenon of frequent urination at night will also occur. If a man has prostatitis, then the inflammation will stimulate the prostate gland to enlarge, thus compressing the bladder and causing a reduction in bladder capacity, and this compression will be more severe at night when sleeping due to the change in position, thus leading to frequent urination at night. For middle aged men with frequent urination, be wary of frequent urination caused by prostate enlargement, which requires a visit to the urology department for further clarification. Diabetes is a common cause of frequent urination at night, and most diabetics have frequent urination at night as an obvious symptom in the early stages. The frequency of urination at night may also be physiological, if you drink a lot of water or eat a lot of diuretic foods, such as watermelon, winter melon and other fruits before going to bed, then you will also experience frequent urination at night.