In the search for a malaria drug, the pharmaceutical chemist Tu Youyou noticed a recipe in the Eastern Jin medical book Zhouhou beiji fang: “Take a handful of qinghao, soak it in two sheng of water, wring out the juice and drink all of it.” Tu then redesigned the research. Her group extracted the plant at low temperature, below 60 degrees Celsius, with water, alcohol, ether and other solvents.
To speed up the work, the group went ahead with homemade methods, tufa shangma. According to Xinhua, they used seven large water vats in place of the usual laboratory vessels. In 1971, in the 191st low-boiling-point experiment, they found a qinghao extract that was 100 percent effective against malaria.