Foam in the urine is common in the following situations: First, men have foam in the urine due to a large drop in urine due to body position, the foam is larger and will dissipate quickly; Second, due to too little water, urine concentration leads to too much inorganic salts, urine tension becomes large, the foam is relatively large at the same time, and can also dissipate quickly; Third, protein urine, such foam is generally fine and small Most of them can last for a long time without dissipating, and the long ones may even last for several hours. If the first two cases are not a big problem, if the foam is caused by proteinuria, it may be caused by various primary glomerulonephritis and various secondary nephritis, such as hypertensive nephropathy, diabetic nephropathy, lupus nephritis, etc.