Adolescent boys often have foam in the urine to consider physiological factors or pathological factors (urinary tract infection, diabetes, kidney disease, etc.). 1. Physiological factors: such as strenuous exercise or urine concentration, it will lead to the presence of foam in the urine, but the foam will usually dissipate quickly, the duration will not be too long, and there are no other clinical symptoms. 2. Pathologic factors (1) urinary tract infection: adolescent boys do not pay attention to lower body hygiene, may induce urinary tract infection, such as urethritis or cystitis, etc., will also make the presence of foam in the urine, but will be accompanied by some urinary abnormalities, such as urinary pain, urinary frequency, urinary urgency. (2) Diabetes: When teenagers suffer from diabetes, it will also make the urine foam, and the bubbles are large, accompanied by excessive drinking, fatigue and other symptoms, which can lead to ketoacidosis in severe cases, and can be diagnosed by blood glucose test. (3) kidney disease: for example, glomerulonephritis, etc., will lead to abnormal renal function of adolescent boys, there are many proteins into the urine, will continue to appear foamy urine, the bubble will be long-lasting, usually accompanied by swelling of the lower limbs, eyelid swelling and other symptoms. Adolescent boys urine often foam, and accompanied by some other obvious abnormalities, should be alert for disease factors, it is recommended that medical examination and treatment, avoid unauthorized use of drugs.