Foamy urine in a 3 year old baby is mostly normal, or it can be abnormal. Normal urine contains some organic and inorganic substances, such as uric acid, creatinine, sodium ions, potassium ions, etc., mixed in the urine into the gas or urine tension is slightly larger and so on, there will be foam, as long as the number of bubbles is not large, and easy to dissipate, generally no problem; If there is a lot of foam and dense and does not dissipate, it suggests the possibility of proteinuria, which is an abnormal situation. When protein can be detected in the urine, it is called proteinuria. The presence of proteinuria suggests that the body may have kidney disease, such as nephrotic syndrome. Parents who find their children’s urine foamy and not easy to dissipate, need to carefully observe the child’s situation, if necessary, can go to the hospital, so as not to delay the condition.