A tiny layer of foam floating on the urine may be a physiological phenomenon, but may also be caused by proteinuria and other causes. 1. A small layer of foam on the urine, if the duration is very short, is generally a normal phenomenon, and drink less water, urination posture, flow rate, etc. have a greater relationship. 2. If the foam lasts a long time does not dissipate, there may be increased solutes in the urine, such as protein, urobilinogen, uroglycerol elevated causes of increased surface tension of urine, more common in a variety of nephritis, diabetes mellitus, hepatic and biliary system diseases, hemolytic disease, and so on. If the foam in the urine does not dissipate after increasing the amount of water consumed, it is recommended to actively consult a doctor, complete the relevant examinations, and carry out treatment under the guidance of the doctor.