Quinine side effects include deafness, low blood platelets, and an irregular heartbeat. Use can make one more prone to sunburn. While it is unclear if use during pregnancy causes harm to the baby, use to treat malaria during pregnancy is still recommended. Quinine is an alkaloid, a naturally occurring chemical compound. How it works as a medicine is not entirely clear. Quinine was first isolated in 1820 from the bark of a cinchona tree. Bark extracts have been used to treat malaria since at least 1632. It is on the World Health Organization's List of Essential Medicines, the most effective and
Cinchona people. Italian sources spelt Quina as Cina which was a source of confusion with "Smilax" from China. Haggis argued that Qina and Jesuit's bark actually referred to "Myroxylon peruiferum" or Peruvian balsam and that this was an item of importance in Spanish trade in the 1500s. Over time, the bark of the "Myroxylon" was adulterated with the similar looking bark of what we now know as "Cinchona". Gradually the adulterant became the main product that was the key therapeutic ingredient used in malarial therapy. The bark was included as "Cortex Peruanus" in the London Pharmacopoeia in 1677. The "fever tree"