Project 523 () is a code name for a 1967 secret military project of the Peoples Republic of China to find antimalarial medications. Named after the date the project launched, 23 May, it addressed malaria, an important threat in the Vietnam War. At the behest of Ho Chi Minh, Prime Minister of North Vietnam, Zhou Enlai, the Premier of the Peoples Republic of China, convinced Mao Zedong, Chairman of the Chinese Communist Party, to start the mass project "to keep [the] allies' troops combat-ready", as the meeting minutes put it. More than 500 Chinese scientists were recruited. The project was divided into three streams. The one for investigating traditional Chinese medicine discovered and led to the development of a class of new antimalarial drugs called artemisinins. Launched during and lasting throughout the Cultural Revolution, Project 523 was officially terminated in 1981.
For their high efficacy, safety and stability, artemisinins such as artemether and artesunate became the drugs of choice in treating falciparum malaria. The World Health Organization advocates their combination drugs and includes them in its List of Essential Medicines. Among the scientists of the project, Zhou Yiqing and his team at the Institute of Microbiology and Epidemiology of the Chinese Academy of Military Medical Sciences, were awarded the European Inventor Award of 2009 in the category "Non-European countries" for the development of Coartem (artemether-lumefantrine combination drug). Tu Youyou of the Qinghaosu Research Center, Institute of Chinese Materia Medica, Academy of Traditional Chinese Medicine (now the China Academy of Traditional Chinese Medical Sciences), received both the 2011 Lasker-DeBakey Clinical Medical Research Award and 2015 Nobel Prize in Physiology or Medicine for her role in the discovery of artemisinin.