Drinking a lot of water and less yellow urine may be physiological factors, gastrointestinal diseases, urinary tract obstruction disease and other factors. 1. Physiological factors: If the human body is in a hot environment or some strenuous exercise, sweating more, resulting in a lack of body fluids, will lead to less yellow urine, should improve the surrounding environment and timely hydration, may be returned to normal. 2. Gastrointestinal diseases: for example, acute gastroenteritis, may be related to unclean diet, will cause frequent vomiting and diarrhea, may consume a lot of water in the body, resulting in concentrated urine, will make the urine less, and yellow, may also be accompanied by fever, abdominal pain and other symptoms. 3. Urinary tract obstruction diseases: such as prostate hyperplasia, urethral stenosis, etc., may hinder the discharge of urine, so that the increase in urine in the bladder, and retention time is too long, it will make the urine less and yellow, and in severe cases, it will also cause urinary retention, unable to discharge urine. Drinking a lot of water and urinating less and yellow may also be caused by other factors, if the symptoms persist and there are other abnormal manifestations, after ruling out physiological factors, it is recommended to go to the regular hospital for medical examination and treatment in a timely manner.