Ignaz Philipp Semmelweis (July 1, 1818 - August 13, 1865), also Ignac Semmelweis (born Semmelweis Ignác Fülöp), was a Hungarian physician called the "savior of mothers" "Ignaz Philipp Semmelweis, the prophet of bacteriology" ("savior of mothers"), O. Hanninen, M. Farago, E. Monos, Department of Physiology, University of Kuopio, Kuopio, Finland, 1983, webpage: blank">GA-Semmelweis-Life-Ideas. "Wanted at birth: clean hands, clean hearts - treating newborns with sensitivity and respect" (on Semmelweis), David B. Chamberlain, Mothering, Winter, 1993, webpage: FindArticles-x8159. who discovered, by 1847, that the incidence of puerperal fever could be drastically cut by use of hand washing standards in _obstetrical clinics. Puerperal fever (or childbed fever) was common in mid-19th-century hospitals and often fatal, with mortality at 10%-35%. "HOW TO IMPROVE YOUR INFORMATION" (various tactics), Frederick Mann, 1993, webpage: blank">Mind-TrekCom-Reports-t103: notes in 1860, 35 of 101 died = 35% mortality.

While working at the Vienna General Hospital in Austria, Semmelweis discovered in 1847 that hand washing with chlorinated lime solutions reduced the incidence of fatal puerperal fever from about 20 percent to about 1 percent. At the time, diseases were attributed to many different and unrelated causes. Each case was considered unique, just like a human person is unique. Semmelweis' postulate, that there was only one cause, that all that mattered was cleanliness, was extreme at the time, and was largely ignored, rejected or ridiculed. He was dismissed from his hospital and had difficulty finding employment as a medical doctor.

Semmelweis was outraged by the indifference of the medical profession and began writing open and increasingly angry letters to prominent European obstetricians, at times denouncing them as irresponsible murderers. His contemporaries, including his wife, believed he was losing his mind and he was in 1865 committed to an asylum (mental institution). Semmelweis died there only 14 days later, possibly after being severely beaten by guards.

Semmelweis' practice only earned widespread acceptance years after his death, when _Louis Pasteur developed the germ theory of disease which offered a theoretical explanation for Semmelweis' findings. Semmelweis is considered the father of antiseptic procedures.