What Does Urine Color Indicate?

9. Blue, Green, or Purple Urine

Many people experience greenish or yellow-colored urine after eating asparagus or foods with green dyes. Asparagus also gives your urine a distinct odor. Often, this is harmless, but sometimes the color can signal a pseudomonas bacterial infection in the urinary tract. Dyes used for some kidney and bladder tests can also make the urine appear blue. Hypercalcemia or "blue diaper syndrome," an inherited metabolic disorder, also turns urine blue. This rare condition develops when the intestines cannot break down tryptophan, a dietary nutrient. Purple urine is seen in catheterized patients and is linked to Gram-negative bacteriuria.