In general, urine rarely has foam formation, when the composition of the urine changes, the surface tension of the urine will be reduced and foam will appear. The following reasons are common: 1, diabetes, this situation is the most common, when the patient has diabetes, urine urine sugar, ketone body content are elevated, will lead to decreased tension. 2, liver and kidney disease, when suffering from liver and kidney disease, urine bilirubin, urine protein and other indicators will be elevated, will also lead to decreased tension. 3, urinary tract infection, inflammation, when the patient has urinary tract infection, such as cystitis, urethritis, prostatitis and other conditions, will also lead to decreased tension. Urethritis, prostatitis and other conditions, will also lead to a decrease in urine tension. 4, urine containing semen or prostate fluid, after intercourse in the same room, due to the components of semen contained in the urethra, the process of urination, will reduce the urine tension, the appearance of foam. You can check the situation yourself, if you consider pathological factors, it is still recommended to seek medical examination in time.