Seeing blood in your urine can be alarming. While in many instances the cause is harmless, blood in urine (hematuria) can indicate a serious disorder or cancer of the urinary tract.

Blood you can see is called gross hematuria, and produces pink, red or cola-colored urine due to the presence of red blood cells. It takes little blood to produce red urine, and the bleeding usually isn't painful. Bloody urine often occurs without other signs or symptoms.

Benign reasons for hematuria include urinary tract infections, urinary tract stones, enlarged prostate or kidney injury. Hematuria usually requires evaluation by a urologist to rule out a cancer-related cause.

Evaluation for hematuria typically includes imaging of the kidneys and cystoscopy — a camera evaluation of the bladder which takes a couple minutes in the urology clinic.