Malaria has been described by WHO as the ‘greatest killer disease in human history’. Although its causation was not understood until the end of the 19th century, its symptoms of fever have been recognised since antiquity. In the period from the 1630s to 1930s, by far the most effective treatment used in Europe and its imperial territories was the quinine alkaloids, contained in the bark of the cinchona tree. Cinchona trees grow high on the eastern slopes of the Andes, and thus for two centuries import of cinchona bark was constrained by uncertain, often monopolistic supply chains, and by limited knowledge of the botany and chemistry of the tree. However, in the period 1850-1870 alkaloid-rich trees were identified, collected and transplanted, leading to the establishment of large plantations in India, Java and throughout the tropics, and the saving of millions of lives.The scientists that drove this emerging understanding during this period of scientific change are as yet little researched. Based on the large cinchona collections within the Economic Botany Department, Royal Botanic Gardens, Kew, this collections based research will trace the networks of exchange, circulation of specimens and key players in this story to shed light upon the development of this important medicine.