Dark red urine is a symptom of what we call hematuria. The symptoms that cause hematuria are the following diseases. I. Stones. When a patient has kidney stones, ureteral stones, bladder or urethral stones, such stones in any part of the body can cut through the urinary epithelium and cause the symptoms of hematuria. Second, inflammation. When acute cystitis, pyelonephritis, urethritis, or even urological tuberculosis occurs, the symptoms of hematuria can occur. Third, tumor. Kidney tumor, bladder tumor, ureteral tumor can cause the symptoms of hematuria. Fourth, trauma. Mainly bladder injury and urethral injury can cause the symptoms of hematuria. Five, congenital malformation. It is seen in polycystic kidney or nephritis, which can cause hematuria. In addition, some systemic bleeding disorders, such as thrombocytopenic purpura, hemophilia, leukemia, and aplastic anemia, can also cause hematuria. Connective tissue diseases such as systemic lupus erythematosus, polyarteritis nodosa, and scleroderma. Infectious diseases such as epidemic hemorrhagic fever, filariasis, and scarlet fever. Cardiovascular diseases such as hemorrhagic heart failure, renal embolism, and deep vein thrombosis can cause hematuria.