For nearly 200 years, the Fugates — known as the blue people of Kentucky — remained largely sealed off from the outside world as they passed their blue skin from generation to generation. //

Cawein devised a cure for this disorder: more blue. Counterintuitively, the best chemical for activating the body’s process of turning methemoglobin to hemoglobin is methylene blue dye. The Fugates he treated ingested this dye and within a few minutes, the blue coloration of their skin disappeared, and their skin turned pink.

As long as they kept ingesting pills of the substance regularly, these blue people of Kentucky could live their lives normally.