Plants that glow under ultraviolet (UV) light aren’t only a figment of science fiction TV and movies. Roots of a traditional medicine plant called the orange climber, or Toddalia asiatica, can fluoresce an ethereal blue hue. And now, researchers have identified two coumarin molecules that could be responsible. These natural coumarins have unique fluorescent properties, and one of the compounds could someday be used for medical imaging.