The historical development of HCQ started way back in 1630's when quinine was first used by Incan descendent in Peru as a traditional way to treat febrile illness from a powder of mystic, the bark of miracle tree which was later (1742) named as cinchona (Cinchona officinalis) by Linnaeus. Later on, in 1820, it was isolated from the cinchona bark by a French chemist, and quinine became a reference treatment for sporadic fever all over the world. In 1930, a related molecule, quinacrine was introduced for the treatment of malaria, however, it was found highly toxic and also inferior compared to quinine. In order to discover an alternative to quinine, in 1934, Hans Andersag and coworkers at the Bayer laboratories synthesized the chloroquine (CQ) and named as Resochin. Later on, CQ was established as a promising antimalarial drug following the US government-sponsored clinical trials under the antimalarial drug development program. Following world war II, CQ and DDT emerged as the two key arms in WHO's global eradication malaria drive. Subsequently, CQ was also found effective in reducing rashes and inflammation (immune suppression) which ultimately led to CQ as an effective medicine for autoimmune disorders, such as rheumatoid arthritis and lupus erythematosus.