Food coloring is the most common cause for blue or green urine. Vitamin B can also turn the urine green. Certain medications like amitriptyline (used for depression or pain), Propofol (sedation and anesthesia during surgery) or indomethacin (an Advil-like pain reliever) can also turn also cause blue/green urine.
The bottom line. If you notice white particles in your urine, it's likely from genital discharge or a problem in your urinary tract, such as kidney stones or possible infection. If you have significant symptoms that accompany the white particles in your urine, you may want to see your doctor.