Causes of hematuria: First, systemic coagulation dysfunction, such as thrombocytopenia or prolonged coagulation time, may cause bleeding from the mucosa of the urinary tract, in addition to skin and mucous membrane bleeding, gum bleeding or vomiting blood, blood in the stool and other symptoms. Secondly, if there is an acute infection in the urinary tract, it can cause mucosal congestion, edema and erosion, then a little blood mixed in the urine will appear hematuria, clinically usually if there is 1ml of blood in 1000ml of urine, that can be manifested as red urine color found by the naked eye. Thirdly, if there are stones in the urinary tract, the stones can cause local mucous membrane to break down, resulting in local bleeding, which can then be manifested as hematuria. Fourth, if there are tumors in the urinary tract, such as kidney tumors, bladder tumors, etc., they may lead to local mucosal destruction or necrosis of the tumor itself, resulting in bleeding, which will then manifest as red urine, requiring ultrasound and CT examination of the urinary system to further exclude.