In 1969, 38-year-old Chinese scientist Tu Youyou was given a task that hundreds of researchers had already spent years trying to solve: finding a new treatment for malaria. The disease was taking a particularly heavy toll on soldiers during the Vietnam War, while the parasite that causes it-the malaria parasite Plasmodium-was becoming increasingly resistant to chloroquine, one of the main antimalarial drugs used at the time.
Two years earlier, the Chinese government had launched a secret research program known as Project 523, named for its start date, May 23, 1967. More than 500 scientists from dozens of institutions took part, and Tu was among them. She approached the work with unusual determination despite still being relatively early in her career. Tu had graduated from the Department of Pharmacy at Peking Medical College, studied medicinal plants at the Academy of Traditional Chinese Medicine, and completed additional training that combined modern pharmacology with traditional Chinese medical practices. That combination would soon prove decisive.
Tu was asked to lead a small team and search for an antimalarial treatment in a place modern pharmacologists would rarely have considered their first choice: ancient medical texts and traditional remedies. Before beginning the work, she traveled to Hainan Island in southern China, where malaria was especially widespread, and saw the disease firsthand-the high fevers, violent chills, and physical exhaustion it caused. The trip required her to leave her children behind. Her younger daughter was only one year old and her older daughter was four, while Tu's husband was also away from home at the time. When Tu returned home several years later, after the malaria research had begun, her younger daughter did not even recognize her.
Back in Beijing, Tu began collecting every reference she could find to treatments for intermittent fever, the recurring episodes of fever and chills characteristic of malaria. Her team studied old medical texts, spoke with practitioners of traditional Chinese medicine, and recorded folk remedies. Within several months, they had gathered more than 2,000 possibilities involving plants, minerals, and animal-derived ingredients. Tu narrowed them down to 640 of the most promising formulas, after which the team began preparing and testing plant extracts.
One plant occasionally produced encouraging results. It was qinghao, or sweet wormwood (Artemisia annua), which had long been used in China to treat fever. The problem was that the effect could not be reproduced consistently: one extract suppressed the malaria parasites, while the next showed almost no activity.
Tu returned to the old texts.
In a fourth-century medical text written by the Chinese physician and alchemist Ge Hong, she noticed an unusual instruction. Instead of boiling qinghao, as was common with many medicinal herbs, the text recommended soaking it in water, squeezing it out, and drinking the resulting liquid. That detail changed the experiment. Tu hypothesized that high temperatures might be destroying the plant's active compound, which would explain why the earlier results had been so inconsistent.
On October 4, 1971, an extract prepared using the new method and labeled No. 191 in the laboratory completely eliminated malaria parasites in infected mice. The result was later reproduced in monkeys. That still did not establish that the treatment was safe for humans: clinical trials were necessary, but carrying them out through the usual procedures was difficult during China's Cultural Revolution, a period of political upheaval that had led to the closure or disruption of much of the country's scientific and academic infrastructure. The researchers also did not want to lose another malaria season, since the number of cases fluctuated throughout the year.
In the summer of 1972, Tu proposed testing the treatment on herself.
She and two colleagues first took the extract under medical supervision in a hospital. No serious side effects appeared. Several other members of the team then tested higher doses, after which the researchers traveled to Hainan to give the treatment to malaria patients for the first time.
The first trial included 21 patients. Their fevers subsided, and the malaria parasites disappeared from their blood. Another nine patients were successfully treated at a hospital in Beijing. After several years of searching, the team finally had convincing evidence that sweet wormwood contained a substance capable of acting against the parasite that causes malaria. That substance became known as artemisinin.
Outside China, however, almost no one knew about the breakthrough. Project 523 had been created as a secret military program, while the Cultural Revolution left Chinese scientists with few opportunities to publish in international journals. The first English-language report on artemisinin appeared only in the late 1970s, and in 1981 Tu presented the findings at an international meeting organized with the participation of the World Health Organization.
Recognition for Tu herself came much later than the discovery. In 2011, she received the Lasker Award, one of the most prestigious honors in biomedical research, and in 2015, at the age of 84, she was awarded the Nobel Prize in Physiology or Medicine "for her discoveries concerning a novel therapy against malaria." A remedy described more than 1,500 years earlier had helped solve a problem modern medicine had struggled to overcome, and Tu Youyou's discovery ultimately transformed malaria from a disease that so often meant death into one that could be treated effectively.
