Yellow and foamy urine in the morning may be a normal physiological phenomenon or a pathological one. If the patient drinks little water, sweats a lot, or holds urine for a long time, yellow urine and foamy urine can appear, and the foamy urine disappears quickly, which is a normal physiological phenomenon at this time. Some diseases can also appear pathological foamy urine, when liver and kidney diseases, such as chronic nephritis, hepatitis, when bilirubin or protein will appear in the urine, it can appear foamy. In cystitis and bladder cancer, bubbles are produced by a change in the composition of the urine. In diabetes, elevated urine sugar or urine ketones appear in the urine, and this time can also appear foamy urine. There are also some bacteria in the urine, and the bacteria produce some gas, which can also appear foamy urine. In short, there are many reasons for foam in urine. When the bubbles increase, the cells are large and last for a long time, you should seek medical guidance and treatment as soon as possible.