Frothy urine means that there is a lot of foam in the urine and can be seen in many conditions. First, it is seen in people with high protein diet, strenuous exercise, and fever. In such people, there can be transient proteinuria in the urine, and the foam increases when the tension of the urine increases. Secondly, it is seen in certain pathological conditions, such as nephrotic syndrome, mainly the barrier of glomerular basement membrane is damaged, permeability is changed, protein in blood can filter through the glomerulus to appear in the tubules, the tubules cannot reabsorb protein, and the urine contains a large amount of protein with foam-like changes. In addition, more foam in urine can also be seen in the increased gas content in urine, seen in people with urinary tract infections, whose causative agent is gas-producing bacteria, such as gas-producing Escherichia coli, which decompose substances in urine and produce gases such as CO2 and NH3, causing foam-like changes in urine.