What causes blood in urine?

A urinary tract infection can cause burning, urgency, frequent urination, and sometimes visible blood. Kidney stones may cause blood with severe pain in the side or groin, while a kidney infection can bring fever, chills, and flank pain. Benign prostatic hyperplasia may affect urine flow in people with a prostate. Blood can also come from the bladder, kidneys, or prostate without pain, including with bladder, kidney, or prostate cancer, so painless visible blood still requires assessment.

Blood may be visible or found only on a urine test. Menstrual blood, vaginal bleeding, or red foods can sometimes be mistaken for urinary blood; a clinician can clarify the source. See [Blood in Urine](/symptoms/blood-in-urine/) for symptom context.

Arrange medical advice for visible blood or a urine test showing blood, even if it happens once or settles. Record pain, fever, urinary changes, recent exercise, medicines, and whether the urine was pink, red, or brown. A clinician may repeat urine testing, check for infection, assess kidney function, or arrange imaging and specialist review according to the findings. Do not self-treat with leftover antibiotics.

Seek urgent care for blood with inability to pass urine, clots blocking flow, severe side or abdominal pain, fever with shaking chills, vomiting, faintness, or rapidly worsening illness. Prompt assessment is also needed when bleeding is heavy or persistent.

Ask whether symptoms fit a [Urinary Tract Infection](/conditions/urinary-tract-infection/), [Kidney Stones](/conditions/kidney-stones/), or [Kidney Infection](/conditions/kidney-infection/); whether prostate or bladder tests are needed; and what changes require urgent care.