Yellow urine may be caused by physiological factors such as drinking too little water and strenuous exercise, or it may be caused by diseases such as urethritis and obstructive jaundice. 1. Physiological factors: If you drink too little water, strenuous exercise, may lead to urine concentration, yellow urine. This kind of situation is a normal phenomenon, usually drink more water, urine can become normal color, no need to worry. 2. Urethritis: Urethritis is mainly caused by gonococcal and non-gonococcal pathogens, patients may have symptoms such as itchy urethra, abnormal urethral secretion, painful urination, etc., and some patients may have yellow urine. 3. Obstructive jaundice: Obstructive jaundice is caused by bile duct obstruction, resulting in increased pressure in the bile duct above the obstruction, bile duct dilatation, and bilirubin in bile flowing back into the blood. Patients may experience yellowing of the skin, yellowing of the urine, abdominal pain, itching of the skin, accompanied by abdominal pain, lethargy, abdominal pain and other symptoms. In addition, there are many causes of yellow urine, it is recommended that patients promptly identify the cause of the disease and actively take relevant treatment measures.