Tu carried on her work in the 1960s and 70s, including during China's Cultural Revolution.During her early years in research, Tu studied Lobelia chinensis, a traditional Chinese medicine believed to be useful for treating schistosomiasis,[9] caused by trematodes which infect the urinary tract or the intestines, which was widespread in the first half of the 20th century in South China.

[citation needed] In 1967, during the Vietnam War, President Ho Chi Minh of North Vietnam asked Chinese Premier Zhou Enlai for help in developing a malaria treatment for his soldiers trooping down the Ho Chi Minh trail, where a majority came down with a form of malaria which is resistant to chloroquine.

Because malaria was also a major cause of death in China's southern provinces, especially Guangdong and Guangxi, Zhou Enlai convinced Mao Zedong to set up a secret drug discovery project named Project 523 after its starting date, 23 May 1967.

By 1971, her team had screened over 2,000 traditional Chinese recipes and made 380 herbal extracts, from some 200 herbs, which were tested on mice.

[10] One compound was effective, sweet wormwood (Artemisia annua), which was used for "intermittent fevers," a hallmark of malaria.

As Tu also presented at the project seminar, its preparation was described in a recipe from a 1,600-year-old traditional Chinese herbal medicine text titled Emergency Prescriptions Kept Up One's Sleeve.

[14] This book instructed the reader to immerse a handful of qinghao in water, wring out the juice, and drink it all.

[3] Since hot water damages the active ingredient in the plant, she proposed a method using low temperature ether to extract the effective compound instead.

In 1973, Tu was attempting to confirm the carbonyl group in the artemisinin molecule when she accidentally synthesized dihydroartemisinin.

[23] Tu is now regarded as a representative figure of the first generation of Chinese medical workers since the establishment of the People's Republic of China in 1949.