Ignaz Philipp Semmelweis (July 1, 1818 – August 13, 1865) (born Ignác Fülöp Semmelweis) is a Hungarian physician now known as an early pioneer of antiseptic procedures.

Described as the "savior of mothers", Semmelweis discovers that the incidence of puerperal fever could be drastically cut by the use of hand disinfection in obstetrical clinics.

Puerperal fever was common in mid-19th-century hospitals and often fatal, with mortality at 10%–35%.

Semmelweis postulates the theory of washing with chlorinated lime solutions in 1847 while working in Vienna General Hospital's First Obstetrical Clinic, where doctors' wards have three times the mortality of midwives' wards.

He publishes a book of his findings in Etiology, Concept and Prophylaxis of Childbed Fever.

Despite various publications of results where hand-washing reduced mortality to below 1%, Semmelweis's observations conflict with the established scientific and medical opinions of the time and his ideas are rejected by the medical community.

Some doctors are offended at the suggestion that they should wash their hands and Semmelweis can offer no acceptable scientific explanation for his findings.

Semmelweis's practice earna widespread acceptance only years after his death, when Louis Pasteur confirms the germ theory and Joseph Lister practices and operates, using hygienic methods, with great success.

In 1865, Semmelweis is committed to an asylum, where he dies, ironically, of septicemia at age 47.