What would cause me to urinate blood? i have had colonoscopy......a few years ago.no immediate threats then.

There : There are multiple causes of visible blood in the urine, but one of the most common is a cancer. This needs to be checked by a urologist without delay.

Bladder infection: Or a kidney stone or other infection in your urinary system. Also tumors of the kidney or bladder can cause hematuria. You need to see your pcp and have a urine culture done. If negative need to see a urologist.