A secret wartime drug hunt found its answer in a 1,600-year-old recipe
Tu Youyou's team screened 2,000 herbal remedies for malaria — the one that worked was a text that said don't boil it.
In 1967, at Ho Chi Minh's request, Mao Zedong authorized a secret military project to find a treatment for a malaria strain resistant to existing drugs, killing soldiers on both sides of the Vietnam War. It was named Project 523 for its start date, and by the time chemist Tu Youyou was put in charge of the herbal-screening team in 1969, researchers worldwide had already tested over 240,000 compounds without a breakthrough.
Tu took a different route. She spent months touring traditional Chinese medicine practitioners and combing classical medical texts, eventually collecting 640 old prescriptions into a notebook and testing extracts from 200 herbs on mice. One plant, sweet wormwood, kept showing partial promise and then failing to reproduce results — until Tu reread a 1,600-year-old text called Emergency Prescriptions Kept Up One's Sleeve, written by the alchemist Ge Hong in the year 340. It specified soaking the herb in cold water and wringing out the juice, not boiling it.
Her team had been extracting with heat the whole time, unknowingly destroying the active compound. Switched to a low-temperature process, the extract worked in animal tests. Tu then volunteered to be the first human subject herself before the drug went to patients.
The compound, artemisinin, is now a first-line malaria treatment worldwide and won Tu Youyou the 2015 Nobel Prize — for listening more carefully to a manuscript than to a century of modern screening.