Daniel Hale Williams was one of the first physicians to perform open-heart surgery in the United States and founded a hospital with an interracial staff.

• Surgeon
  (1856–1931)

African-American chemist Percy Julian was a pioneer in the chemical synthesis of medicinal drugs such as cortisone, steroids and birth control pills.

• Medical Professional, Civil Rights Activist, Scientist, Chemist, Academic
  (1899–1975)

Prussian physician Robert Koch is best known for isolating the bacterium which causes tuberculosis, the cause of numerous deaths in the mid-19th century.

• Medical Professional, Scientist, Biologist
  (1843–1910)

James D. Watson is a Nobel Prize-winning biophysicist and researcher credited with co-discovering the double-helix structure of DNA.

• Biologist, Geneticist, Academic, Zoologist, Scientist
  (1928–)

Scientist Louis Pasteur came up with the food preparing process known as pasteurization; he also developed vaccinations for anthrax and rabies.

• Chemist, Inventor, Scientist
  (1822–1895)

Charles Drew was an African-American surgeon who pioneered methods of storing blood plasma for transfusion and organized the first large-scale blood bank in the U.S.

• Surgeon, Doctor, Educator
  (1904–1950)

Jonas Salk was an American physician and medical researcher who developed the first safe and effective vaccine for polio.

• Scientist, Doctor
  (1914–1995)

Alexander Fleming was a doctor and bacteriologist who discovered penicillin, receiving the Nobel Prize in 1945.

• Scientist, Biologist
  (1881–1955)

Bennet Omalu discovered Chronic Traumatic Encephalopathy in former football players, sparking years of denial from the NFL and the creation of a movie about his life's work.

• Doctor, Medical Professional
  (1968–)

Elizabeth Stern was a pathologist who identified 250 stages of a cervical cells' progression from normal to cancerous, a breakthrough in women’s health that enabled early cancer detection and treatment.

• Medical Professional, Doctor, Scientist
  (1915–1980)

Neurologist and author Oliver Sacks has written numerous works on patients with often unusual conditions. His titles include ‘Awakenings’ and ‘The Man Who Mistook His Wife for a Hat.’

• Scientist, Neurologist, Educator, Psychiatrist
  (1933–2015)

Alois Alzheimer was a German psychiatrist who discovered the pathological condition of dementia and diagnosed the disease that bears his name.

• Neurologist, Scientist, Psychiatrist
  (1864–1915)

A pioneer in early hormonal and reproductive research, Gregory Pincus and his team of scientists are credited with formulating the first oral contraceptive for birth control.

• Scientist, Doctor, Biologist
  (1903–1967)

Paul C. Lauterbur is an American chemist best known for his work in helping to develop magnetic resonance imaging (MRI) for internal body structures scanning.

• Chemist, Scientist, Educator
  (1929–2007)

American neuroscientist Richard Axel is best known for his work on the olfactory system, exploring how the brain interprets smell.

• Neurologist, Scientist
  (1946–)

Peter Agre won the Nobel Prize for Chemistry in 2003 for his discovery of the protein aquaporin which led to later important scientific breakthroughs.

• Doctor, Medical Professional
  (1949–)

Rudolf Virchow was a 19th century German pathologist and politician known for his significant findings in social medicine.

• Academic, Scientist, Biologist, Doctor
  (1821–1902)

Surgeon Norman Shumway performed the first human heart transplant in 1968.

• Surgeon
  (1923–2006)

Walter Reed was a U.S. Army pathologist and bacteriologist who led the experiments that proved that yellow fever is transmitted by mosquito bite.

• Medical Professional, Scientist, Doctor
  (1851–1902)

Severo Ochoa was a Spanish-American biochemist and molecular biologist who was co-awarded the 1959 Nobel Prize in Physiology or Medicine for discovering an enzyme that enables the synthesis of RNA.

• Academic, Chemist, Scientist
  (1905–1993)

Rita Levi-Montalcini shared the 1986 Nobel Prize for physiology or medicine for her part in the discovery of a protein that stimulates nerve cell growth.

• Medical Professional, Educator, Neurologist, Academic
  (1909–2012)

Ernest O. Lawrence was a nuclear physicist known for his work on the Manhattan Project and for the invention of the cyclotron, for which he won the Nobel Prize.

• Educator, Inventor, Scientist, Physicist
  (1901–1958)

Immunologist and pathologist Karl Landsteiner received the Nobel Prize for Physiology or Medicine for his discovery of the major blood types.

• Scientist, Immunologist
  (1868–1943)