What are the causes of blood in the urine?

Blood in the urine (hematuria) may be caused by various factors, mainly including: 1. **Urinary system diseases**: Such as urethritis, cystitis, glomerulonephritis, urinary system stones (kidney stones, ureteral stones, etc.), urinary system tuberculosis, and urinary system tumors. These conditions may cause damage to the mucous membranes of the urethra or bladder, leading to hematuria. 2. **Systemic diseases**: Such as sepsis, epidemic hemorrhagic fever, leukemia, and aplastic anemia. These diseases may affect the normal function of the kidneys or urinary system, resulting in hematuria. 3. **Lesions in organs adjacent to the urinary system**: Such as chronic prostatitis, seminal vesiculitis, female pelvic inflammatory disease, cervical cancer, etc. These conditions may affect the urinary system and cause hematuria. If hematuria is suspected, prompt medical consultation and diagnosis are recommended.