The origins of our best drug against malaria have long been a mystery. Meet Tu Youyou , who scoured ancient Chinese medical texts for the cure

Tu Youyou, now 80, continues to study artemisinin at her lab in Beijing Simon Griffiths

Update: Tu Youyou has been awarded a share of the 2015 Nobel Prize for medicine or physiology for her discovery of artemisinin. She shared the prize with William C. Campbell and Satoshi Ōmura, whose work led to the development of ivermectin, an important treatment for roundworm parasite diseases.

FORTY years ago a secret military project in communist China yielded one of the greatest drug discoveries in modern medicine. Artemisinin remains the most effective treatment for malaria today and has saved millions of lives. Until recently, though, the drug’s origins were a mystery.

“I was at a meeting in Shanghai in 2005 with all of the Chinese malariologists and I asked who discovered artemisinin,” says Louis Miller, a malaria researcher at the US National Institutes of Health in Rockville, Maryland. “I was shocked that no one knew.”

Miller and his NIH colleage Xinzhuan Su began digging into the drug’s history. After reviewing letters, researchers’ original notebooks and transcripts from once-secret meetings, they concluded the major credit should go to pharmacologist Tu Youyou. Two months ago Tu received America’s top medical accolade, the Lasker award.

Now 80, Tu still runs a lab in Beijing where she continues to study artemisinin. Shortly before receiving the award she met me at a hotel near New York’s Central Park. Joining us was her son-in-law, Lei Mao, a physician living in North Carolina, who served as interpreter.

Tu is a diminutive figure with short, jet black hair that curls in wisps around her ears. Reading glasses dangle from a chain …