Urine yellow deposited underneath the toilet, the possible causes: a. Urine concentration leads to yellow urine, such as excessive water loss or drinking less water, or holding urine for a long time without urination, is possible to cause urine concentration and yellow color. When urinating because the specific gravity is too high, and the yellow urine is deposited below the water, the above symptoms will appear. It is usually not accompanied by a history of frequent urination, urgent urination, painful urination, etc. The color of urine can return to normal after drinking more water. Second, if there is an infection of the urinary tract, the urine contains more urine pigment or bacteria, etc., causing the decomposition of the proteins in the urine and producing yellow urine color and odor, there can also be an increase in the specific gravity of urine, which will be deposited below the toilet when urinating, and can also be manifested as frequent urination, urinary urgency, painful urination or accompanied by cloudy urine, etc. It is necessary to carry out routine urine examination to further confirm the diagnosis. Third, elevated bilirubin and urobilinogen content in urine can also lead to increased specific gravity and yellow color, which will also be deposited under the toilet water.