Chloroform is a colorless liquid that is used as an anesthetic. The compound was discovered in 1831 independently by Samuel Guthrie (1782-1848) of New York, Eugene Soubeiran (1797-1858) of France, and Justus von Liebig of Germany. (Guthrie, an American chemist and physician, also introduced Edward Jenner's vaccination technique to the United States.) M. J. Dumas of Paris described the composition of the new liquid and gave it the name "chloroform" in 1834 or 1835. The Frenchman Marie-Jean-Pierre Flourens (1794-1867) noted the anesthetic effect of chloroform on animals in March 1847.

Sir James Young Simpson, an eminent Scottish obstetrician, introduced the medical use of chloroform as an anesthetic in Edinburgh in November 1847. Earlier that year, Simpson had begun using ether to alleviate the pain of childbirth, but was dissatisfied with some of ether's drawbacks, such as the large quantities required and the lung irritation it caused. A Liverpool chemist, David Waldie, suggested that Simpson try chloroform instead. On the evening of November 4, 1847, Simpson and two doctor friends inhaled some chloroform and promptly passed out. Impressed with chloroform's potency and rapid effects, Simpson immediately began using it in his obstetrical practice.

Scottish clergymen just as quickly objected to this use of anesthesia, insisting the pain of childbirth was ordained by God. Simpson countered by citing the biblical account of the deep sleep cast on Adam when God took the first man's rib. The argument continued until 1853, when Queen Victoria (1819-1901) chose to be chloroformed for the birth of her son Prince Leopold (1853-1884). This event quieted the clergy and ensconced chloroform as the most fashionable and popular anesthetic in England and the rest of the Western world for the next 50 years.

Although chloroform did carry some risk of heart failure, it was more pleasant to take and more powerful than ether. Queen Victoria 's anesthetist, Dr. John Snow (1813-1858), developed an inhaler to regulate the amount of chloroform administered to a patient. Snow's research greatly contributed to the safety of the anesthetic. Chloroform finally fell out of favor when oxygen -gas mixtures regained popularity around 1900.