You know how urine has been boring old yellow for thousands of years, well now we have evolved to new and improved purple!

Well, not exactly, this is a phenomenon quite literally named, Purple Urine Bag Syndrome. It was first described in 1978, when elderly patients with catheters began filling their urine bags with grape juice colored urine. What is interesting is that patients don’t complain of any symptoms, purple discoloration of urine is often the only finding.

The cause is simple enough, bacteria (Klebsiella pneumoniae) in the urine produce the enzyme indoxyl phosphatase. This converts indoxyl sulfate in the urine into the red and blue colored indirubin and indigo compounds, respectively. Easy right?

If you would like your urine to turn funny colors, check out this site with tips on how.