Every medical intervention—even one with a centuries-long history—brings dangers, some of which become clear only later.

Centuries of folklore backed by scientists in the early 1900s have perpetuated the idea that menstruating women can exert dangerous forces.

Soranus of Ephesus’s manual shaped the way midwifery was practiced for more than a millennium.

A contaminated ham put bacteriologist Émile Pierre-Marie van Ermengem on the path to discovering the microbe that produces botulinum toxin.

Ruth Ella Moore had a trailblazing career, overcoming barriers of racism and sexism as she pursued her interest in microbiology.

A controversial idea from the mid-20th century is attracting renewed attention from researchers developing theories for how cognition arises with or without a brain.

Trofim Lysenko’s attacks on geneticists had long-term effects on Russian science and scientists, despite a lack of evidence to support his beliefs about biological inheritance.

Historical and modern experiments have hinted that unicelluar organisms can learn from their experiences, but the idea still has its critics.

One hundred years after its invention, BCG has stood the test of time as a vaccine against tuberculosis.

A famous account of multiple personality disorder in the early 20th century foreshadowed a century of controversial diagnoses and debate among psychiatrists.

The “mother of plant virology and serology,” Helen Purdy Beale, developed techniques to understand the nature of viruses that went unappreciated for decades.

As a deadly smallpox outbreak ravaged Boston, one of the city’s leaders advocated for a preventive measure he’d learned about from Onesimus, an enslaved man.

Watch Nobel Laureate Rita Levi-Montalcini tell the story of how she continued her transformative cell biology research as World War II raged.

Neuroscientist Rita Levi-Montalcini began her Nobel Prize–winning work in a makeshift laboratory in Italy during the Second World War.

Lore has always surrounded argonauts, pelagic octopuses that build shells and travel the seas.

In the past, it was not uncommon for researcher to test their experimental therapeutics and vaccines on themselves. Some even volunteered to be exposed to pathogen-carrying vectors.

Electron microscopy revealed that a deadly disease of birds was not a form of flu, but a different type of virus entirely.

A new book explores the history of scientists’ efforts to classify living things.

Scientists are taking their own vaccines, an ethically murky practice that has a long and sometimes celebrated history in medicine.