There is a lot of foam in the urine, first of all, to clarify the presence of proteinuria, urine routine examination. Normal people will have some foam in their urine, but it is small and lasts for a short period of time. If the foam is large and lasts for a long time, it is an abnormal type of foam. The most common cause of urine foam is the presence of urinary protein in the urine, which is mainly seen in all kinds of nephritis, especially chronic nephritis. If it is really chronic nephritis, then basically can develop into renal failure. Therefore, if you suspect nephritis, you have to complete the routine urine examination to observe whether there is protein in the urine. Another thing that can cause foam in the urine is urinary tract infection, and among the urinary tract infections, acute pyelonephritis is the most harmful, which can cause perinephric abscess, renal papillary necrosis, and after the bacteria enter into the bloodstream, it will develop into bacteremia and sepsis. The main diagnosis of this disease is to carry out routine urine examination to see if there are white blood cells; urine culture examination to see if the bacteria are cultured.