An 88-year-old woman came to a hospital in Chiba, Japan, weak and only partly alert. Her blood work was normal. So were her imaging and neurological findings. Then her emergency physicians took a second look and noticed something no scan could show: her tongue had turned blue.
That color led the team at Toho University Medical Center Sakura Hospital to a diagnosis. The woman, who had a history of insomnia, had accidentally taken flunitrazepam, a powerful benzodiazepine sleeping pill, by licking the tablet like a piece of candy. Ryo Ichibayashi and Miwako Togawa described the case in a report published in Cureus in May 2024, and it has since become one of several Japanese reports in which a drug's built-in dye pointed doctors to a hidden exposure.
