After the body rests overnight, the kidneys discharge urine that is mostly concentrated, and this urine is often discharged for the first time in the early morning and is dark yellow. Some patients drink more water before going to bed, and the color of urine the next day is light yellow, or even clear, transparent urine. If there is no discomfort in urination, this is nothing to worry about, it is all in the normal color category. If the color is dark yellow or dark reddish brown, you need to rule out hemoglobinuria or bilirubinuria. Patients with significant changes in urine color will have clinical symptoms. Therefore, it is recommended that when symptoms appear, the urine routine should be checked first to clarify whether there are changes in specific items of the urine routine before targeted treatment. Therefore, if a patient finds dark urine in the morning, there is no need to worry if there are no uncomfortable symptoms, as they all belong to the normal color range.