Researchers in Israel took fresh urine samples from 17 young people with ulcerative colitis, added one milliliter of hypochlorous acid, the reactive chemical found in household bleach, to each, and watched. Every sample from a patient taking mesalamine turned brown on contact. None of the samples from patients on other drugs changed at all.
The prospective case-control study, published online in April and in the June issue of Minerva Gastroenterology, puts hard numbers on a phenomenon that has circulated for years in patient forums and scattered case reports: urine that looks alarmingly bloody in the toilet bowl and perfectly normal in a specimen cup.
