Artemisinin, also known as qinghao su (Chinese: 青蒿素), and its semi-synthetic derivatives are a group of drugs that possess the most rapid action of all current drugs against Plasmodium falciparum malaria. It was discovered by Tu Youyou, a Chinese scientist, who was awarded half of the 2015 Nobel Prize in Medicine for her discovery. Treatments containing an artemisinin derivative (artemisinin-combination therapies, ACTs) are now standard treatment worldwide for P. falciparum malaria. Artemisinin is isolated from the plant Artemisia annua, sweet wormwood, an herb employed in Chinese traditional medicine. A precursor compound can be produced using genetically engineered yeast.