The visible sign of hematuria is pink, red or cola-colored urine — the result of the presence of red blood cells. It takes very little blood to produce red urine, and the bleeding usually isn't painful. If you're also passing blood clots in your urine, that can be painful. Bloody urine often occurs without other signs or symptoms.
It's possible to have blood in your urine that's visible only under a microscope (microscopic hematuria).
When to see a doctor
Make an appointment to see your doctor anytime you notice blood in your urine.
Some medications, such as the laxative Ex-lax, and certain foods, including beets, rhubarb and berries, can cause your urine to turn red. However, blood in the urine looks distinctly different.
A change in urine color caused by drugs, food or exercise may go away within a few days. But you can't automatically attribute red or bloody urine to medications or exercise; that's why it's best to see your doctor anytime you see blood in your urine.