To avoid spreading illnesses like influenza and coronavirus, perhaps the least controversial—and most effective—tactic is to wash your hands. The Center for Disease Control advocates a 20-second scrub with soap and water, but this advice wasn’t always considered common sense. In the 19th century, it was scandalous.

In Europe in the 1840s, many new mothers were dying from an ailment known as puerperal fever, or childbed fever. Even under the finest medical care available, women would fall ill and die shortly after giving birth. Hungarian physician Ignaz Semmelweis was intrigued by the problem and sought its origins. (How trillions of microbes affect our everyday life.)

View Images Hungarian physician Ignaz Semmelweis was an early pioneer of antiseptic procedures but was ridiculed for his work linking handwashing to better medical care. Photograph by GL Archive, Alamy

Midwives and doctors

Semmelweis worked in the Vienna General Hospital in Austria, which had two separate maternity wards: one staffed by male doctors and the other by female midwives. He noticed that the mortality rate from the fever was much lower when midwives delivered babies. Women under the care of doctors and medical students were dying at more than twice the rate of the midwives’ patients.

The doctor tested a number of hypotheses for the phenomenon. Semmelweiss investigated whether a woman’s body position during birth had an impact. He studied if the literal embarrassment of being examined by a male doctors was causing the fever. Perhaps, he thought, it was the priests attending to patients dying of the fever that scared the new mothers to death. Semmelweis assessed each factor and then ruled them out.

Particles and pathogens

After removing these other variables, Semmelweis found the culprit: cadavers. In the mornings at the hospital, doctors observed and assisted their students with autopsies as part of their medical training. Then, in the afternoons, the physicians and students worked in the maternity ward examining patients and delivering babies. The midwives had no such contact: They only worked in their ward.

Semmelweis hypothesized that “cadaverous particles” were being transferred from dead bodies to new mothers by the doctors and their students. Physicians did not have to scrub their hands in between patient visits, unlike today. Whatever pathogens they came in contact with during an autopsy would be taken into the maternity ward.

View Images Painter Robert Thom depicts Semmelweis (center) in the Vienna General Hospital in Austria overseeing doctors washing their hands before examining obstetric patients. Photograph by Look and Learn, Bridgeman Images

Germ theory was in still in its infancy (scientists Louis Pasteur and Joseph Lister were a few decades away from their influential work), so rather than “germs” Semmelweiss called the agents “decomposing animal organic matter.” Women became infected with the particles and died of the fever after coming into contact with the doctors. (Before vaccines, smallpox killed 3 out of 10 infected people.)

Show of hands

In 1847, Semmelweis implemented mandatory handwashing among the students and doctors who worked for him at the Vienna General Hospital. Rather than relying on plain soap, Semmelweiss used a chlorinated lime solution because it totally removed the smell of decay that lingered on the doctors’ hands. The staff began sanitizing themselves and their instruments. The mortality rate in the physician-run maternity ward plummeted.

In the spring of 1850, Semmelweis took the stage at the prestigious Vienna Medical Society and extolled the virtues of hand washing to a crowd of doctors. His theory flew in the face of accepted medical wisdom of the time and was rejected by the medical community, who faulted both his science and his logic. Historians believe they also rejected his theory because it blamed them for their patients’ deaths. Despite reversing the mortality rates in the maternity wards, the Vienna Hospital abandoned mandatory handwashing.

The ensuing years were difficult for Semmelweis. He left Vienna and went to Pest in Hungary where he also worked in a maternity ward. He instituted his handwashing practice there and, as in Vienna, drastically reduced the rate of maternal mortality. Yet his success at saving lives earned no acceptance of his ideas.

Semmelweis published articles on handwashing in 1858 and 1860 followed by a book a year later, but his theories were still not embraced by the establishment. His book was widely condemned by doctors with other theories for the continuing spread of childbed fever.

A few years later, Semmelweis’s health began to deteriorate. Some believe he was suffering from syphilis or Alzheimer’s disease. He was committed to a mental institution and died not long after, possibly due to sepsis caused by an infected wound on his hand.

A doctor's redemption

In 1867, two years after Semmelweis’ death, Scottish surgeon Joseph Lister also propelled the idea of sanitizing hands and surgical instruments to halt infectious diseases. His ideas had their critics, too, but in the 1870s physicians began regularly scrubbing up before surgery.

Not long after, others began to recognize the earlier work of Semmelweis. His work later led to Louis Pasteur’s development of germ theory, which changed how doctors care for their patients and investigate the cause and spread of diseases. (Teaching people to be healthy has come a long way.)

View Images In a sketch, Semmelweis washes his hands in chlorinated lime solution. Although his work led to safer medical practices, it was not recognized until after his death in 1865. Photograph by Bettmann, Getty