Yellowish urine in babies may be caused by physiological factors, such as diet, medication factors, concentrated urine, etc. It may also be caused by liver and gallbladder diseases, gastrointestinal diseases and so on. The baby ate more carrots, mango, papaya or ate some vitamin B drugs, can lead to dark yellow urine. Babies who drink less water or sweat more can cause the urine to become concentrated and the urine can become darker in color. All of these conditions are significantly improved by increasing fluid intake. Babies who have diarrhea and lose a lot of fluids through the intestines can also lead to a decrease in urine output and yellowing of the urine. Hepatobiliary pathology and neonatal jaundice can lead to abnormal bilirubin metabolism, which increases the amount of urobilinogen in the urine, and the yellowing of urine can be accompanied by yellowing of the skin. Babies with yellow urine color, if there is no significant improvement by increasing the amount of fluid, should be timely to the hospital.