Purple urine bag syndrome: case report and literature review.

Purple urine bag syndrome (PUBS) is a medical syndrome in which there is purple discoloration of the urine of catheterized patients as well as discoloration of the collecting bag and the associated tubing. This rare condition, which mostly affects women, is generally associated with catheter-associated urinary tract infection, chronic constipation and alkaline urine. PUBS may be caused by sequential chemical reactions involving tryptophan from food in the gastrointestinal tract. The clinical course of PUBS is generally benign, and intensive treatment is not usually needed. We present 3 cases of this unusual and interesting phenomenon and a literature review.