Fluorescence detection of poison oak oil: Tens of millions of Americans suffer every year after close encounters with urushiol, the oily allergen in poison oak and poison ivy. The barest brush of urushiol-tainted foliage, clothing or fur against the skin is often all that is needed to set off a severe allergic reaction, and by the time itching sets in, it is too late to avoid a rash. After experiencing a particularly nasty run-in with poison oak, Rebecca Braslau of the University of California, Santa Cruz, decided to fight back—with science. “I was thinking, ‘I'm a chemist—I should be able to do something with this,’” she recalls. Patent no. 8,389,232 B2 details her invention, a substance that fluoresces in the presence of urushiol and gives an early warning to wash the allergen off. “It's a spray that you can put on clothing and tools,” Braslau says. “Then you can hold the sprayed areas up to a fluorescent light to see the oils—they glow blue.” She plans to test it on human skin soon. The invention, Braslau says, could help hikers, firefighters, rescue workers, farmers and anyone else who spends time outdoors.