The medicinal value of "Artemisia annua" has been used by Chinese herbalists in traditional Chinese medicines for 2,000 years. In 1596, Li Shizhen recommended tea made from qinghao specifically to treat malaria symptoms in his "Compendium of Materia Medica". Artemisinins, discovered by Chinese scientist Tu Youyou and colleagues in the 1970s from the plant "Artemisia annua", became the recommended treatment for "P. falciparum" malaria, administered in severe cases in combination with other antimalarials. Tu says she was influenced by a traditional Chinese herbal medicine source, "The Handbook of Prescriptions for Emergency Treatments", written in 340 by Ge Hong. For her work on malaria, Tu Youyou received the 2015 Nobel Prize in Physiology or Medicine.