We Had A Cure For Leprosy For Centuries, But Couldn't Get It To Work

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People in China discovered the cure for leprosy in the 1300s, and yet for six hundred years, the cure didn’t actually work. We’ll tell you why a known cure wasn’t good enough, and how to make it good enough.

The chances that you’ll get leprosy are vanishingly small. That’s a good thing at any time, but it was especially good any time before 1916. Sure, people had a “cure.” It was called Chaulmoogra oil, and they’d had it for hundreds of years. The problem was, they had it in extremely the wrong form.


Chaulmoogra extract, taken from the seed of the Chaulmoogra tree, was too viscous to be effective as an oil and too big to be effective as a salt. Leper “asylums” did use the oil by injecting it, but the treatment was horribly painful because the oil would stick together under the skin like a blister. Images of the treatment show row after orderly row of lightly-bleeding bubbles of oil, as if the patient’s skin had been replaced with bubble wrap.

Someone had to find a way to get the oil to circulate around the body, and in 1916, someone did. Alice Ball, a chemist, had been working on the problem for only a year when she figured out a way to get the ingredients that fought leprosy into a form that could circulate through the body. She took the fatty acids present in the oil and she exposed them to an alcohol. What could this do? As we’ve mentioned before, combining carboxylic acids with alcohol gets you an ester. (You’ll also find fatty acids attached to alcohol to form esters in Omega 3 supplements today.)


Ethyl esters were soluble in water, and could move around the body. By 1922, “The Ball Method,” was widely used to prepare chaulmoogra oil. Doctors sang its praises. People who had expected to be in leper asylums, subjected to constant, painful injections, for the rest of their lives suddenly were discharged. The cure that everyone knew was a cure finally worked.


Tragically, Alice Ball never saw the full results of her discovery. Less than a year after she made the discovery, she was exposed to chlorine gas during a lecture. She died soon afterwards, at age 24.

Top Image: Tropenmuseum Alice Ball Image: University of Hawaii

[Source: Chem History, International Medical and Surgical Survey]