10 Most Influential Danish Doctors Throughout History

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Heritage Digest

11 min readAug 24, 2024

Denmark has long been home to some of the most pioneering doctors in medical history. From groundbreaking research to revolutionary practices, these Danish medical professionals have left an indelible mark on the world. Here, we explore ten of the most influential Danish doctors whose contributions have shaped healthcare in Denmark and had a global impact.

Niels Ryberg Finsen (1860–1904)
Johannes Fibiger (1867–1928)
August Krogh (1874–1949)
Hans Christian Gram (1853–1938)
Carl Peter Henrik Dam (1895–1976)
Niels Kaj Jerne (1911–1994)
Thomas Bartholin (1616–1680)
Mogens Schou (1918–2005)
Caspar Bartholin the Elder (1585–1629)
Carl Lange (1834–1900)

1. Niels Ryberg Finsen (1860–1904)

Niels Ryberg Finsen, born on December 15, 1860, in Tórshavn, Faroe Islands, emerged from a family with deep Icelandic roots and a Danish connection through his mother. Despite a challenging upbringing, especially after his mother’s death and his struggle at Herlufsholm School, Finsen’s determination led him to pursue medicine, graduating from the University of Copenhagen in 1890. His early experiences, marked by adversity and resilience, shaped his path toward becoming a pioneer in phototherapy.

Finsen’s groundbreaking work in treating diseases, particularly lupus vulgaris, with concentrated light radiation, revolutionized medical approaches to disease treatment and established him as the founder of modern phototherapy. His dedication to understanding the therapeutic effects of light on skin diseases culminated in him receiving the Nobel Prize in Physiology or Medicine in 1903. This accolade not only honored his contributions to medical science but also highlighted the global significance of his research.

Towards the end of his life, Finsen’s health deteriorated, yet his intellectual vigor remained unscathed. He continued his work despite physical limitations, a testament to his unwavering commitment to science and healing. Finsen passed away on September 24, 1904, in Copenhagen, but his legacy lives on through institutions like the Finsen Institute and memorials that honor his life and work. His pioneering spirit in phototherapy opened new avenues in medical science, ensuring his place as a key figure in medical history.

2. Johannes Fibiger (1867–1928)

Johannes Fibiger was born on April 23, 1867, in Silkeborg, Denmark, into a family where his father was a physician and his mother an author. Despite the early loss of his father, Fibiger pursued an education in medicine, graduating from the University of Copenhagen in 1890. His upbringing, marked by personal loss and the influence of a medically oriented family, steered him towards a distinguished career in medical research, particularly in pathological anatomy.

Fibiger’s most notable achievement was his work on Spiroptera carcinoma (later corrected to Gongylonema neoplasticum), which he mistakenly believed could induce cancer in rats. This work led to him being awarded the Nobel Prize in Physiology or Medicine in 1926, marking him a cancer research pioneer despite later findings contradicting his conclusions. His contributions extended beyond this discovery; he was also instrumental in advancing the research methodology in medicine, particularly through his work on diphtheria, considered the origin of the controlled clinical trial.

Fibiger passed away on January 30, 1928, leaving a pioneering and controversial legacy. After his death, it was proven that G. neoplasticum does not cause cancer and that the observed tumors were due to vitamin A deficiency. Despite this, Fibiger’s methodological contributions to medical research, including his early implementation of controlled clinical trials, remain a significant part of his legacy. His work laid the groundwork for future generations in medical research, illustrating both the potential and the pitfalls of scientific discovery.

3. August Krogh (1874–1949)

August Krogh was born on November 15, 1874, in Grenaa, Denmark, into a family where his father was a shipbuilder. His upbringing in the industrious environment of Djursland influenced his later dedication to scientific research. Krogh pursued his education in science, completing a Master of Science in 1899 and a Ph.D. in 1903 at the University of Copenhagen. His early academic achievements set the stage for a prolific career in physiology.

Krogh’s contributions to the field of physiology were groundbreaking. He was awarded the Nobel Prize in Physiology or Medicine in 1920 for discovering the regulation mechanism of capillaries in skeletal muscles, a fundamental aspect of muscle physiology. His work laid the foundation for understanding how blood flow is adapted in different tissues based on their needs. Additionally, Krogh was instrumental in founding Novo Nordisk, a global leader in diabetes care, showcasing his impact beyond academia into practical medical applications.

Krogh passed away on September 13, 1949, but his legacy endures through his numerous scientific contributions and the establishment of Nordisk Insulinlaboratorium with his wife, Marie. Their work bringing insulin production to Denmark significantly advances diabetes treatment. Krogh’s life and career exemplify a profound dedication to improving medical science and health care, making him a pivotal figure in the history of physiology.

4. Hans Christian Gram (1853–1938)

Hans Christian Joachim Gram, born on September 13, 1853, in Denmark, was the son of a professor of jurisprudence. Growing up in an intellectually stimulating environment, he initially explored botany, introducing him to pharmacology and microscopy. This early exposure laid the groundwork for his future scientific endeavors. Gram pursued medical studies at the University of Copenhagen, graduating in 1883, and spent years traveling and learning throughout Europe, enriching his medical and scientific knowledge.

Gram’s most notable achievement came in 1884 in Berlin, where he developed the Gram staining technique. This method revolutionized microbiology by classifying bacteria into Gram-positive and Gram-negative based on their staining properties. Despite Gram’s modesty about his discovery, the technique became foundational in medical microbiology, enabling more precise identification and treatment of bacterial infections. His work earned him international acclaim and profoundly impacted the field of bacteriology.

Gram continued his career as a professor at the University of Copenhagen, contributing significantly to medical education until his retirement in 1923. He passed away on November 14, 1938, leaving behind a legacy celebrated by the scientific community. His great-granddaughter, Lone Gram, continues the family’s scientific tradition as a microbiologist, underscoring the lasting impact of Gram’s work on subsequent generations.

5. Carl Peter Henrik Dam (1895–1976)

Carl Peter Henrik Dam, born in Denmark on February 21, 1895, was a pivotal figure in biochemistry and physiology. His upbringing led him to pursue a career in science, culminating in groundbreaking research that would have a lasting impact on medical and nutritional understanding. Dam’s education began with an undergraduate degree in chemistry from the Copenhagen Polytechnic Institute, where he was quickly recognized for his talent, leading to a position as an assistant instructor in chemistry.

In the early 20th century, Dam embarked on a research journey that would lead to the discovery of vitamin K, a substance critical for blood coagulation. Through meticulous experimentation, including feeding chickens a cholesterol-free diet, Dam, alongside Edward Doisy, identified the presence of an essential compound apart from cholesterol, responsible for preventing animal hemorrhages. This discovery was monumental, shedding light on the intricate mechanisms of blood coagulation and introducing vitamin K as a crucial nutrient for human health.

Dam’s contributions to biochemistry were internationally acknowledged when he was awarded the Nobel Prize in Medicine in 1943, a testament to the significance of his work on vitamin K. Beyond this accolade, Dam continued to explore the biological significance of sterols, contributing to the broader field of physiology and nutrition. His career, marked by a dedication to advancing scientific knowledge and a tenure at the University of Rochester, solidified his legacy as a pioneer in understanding the vital roles of vitamins in human physiology. Dam passed away on April 17, 1976, leaving behind a legacy of scientific innovation that continues to influence medical and nutritional sciences.

6. Niels Kaj Jerne (1911–1994)

Niels Kaj Jerne, born on December 23, 1911, in London to Danish parents, was a pioneering figure in immunology whose work reshaped our understanding of the immune system’s function and development. His education, initially in physics at Leiden University and later in medicine at the University of Copenhagen, where he earned his degree in 1947, laid the foundation for his innovative research. His family's academic background nurtured Jerne’s early interest in the sciences, setting the stage for his groundbreaking contributions to medical science.

Jerne’s most significant achievement was the introduction of theories that revolutionized immunology, earning him the Nobel Prize in Physiology or Medicine in 1984. His hypothesis that the immune system possesses preformed antibodies ready to combat antigens challenged existing paradigms and introduced a new understanding of immune response mechanisms. Furthermore, Jerne’s network theory, which described how antibodies recognize and interact with each other and antigens, provided a comprehensive model for the adaptive immune system’s complexity and dynamism.

Throughout his career, Jerne’s positions at prestigious institutions, including the World Health Organization and the Basel Institute for Immunology, allowed him to further his research and mentor the next generation of scientists. His work laid the groundwork for developing monoclonal antibodies and transforming medical diagnostics and treatment. Jerne’s legacy is his contribution to immunology and his role in fostering a deeper understanding of the immune system’s intricate workings. He passed away on October 7, 1994, leaving behind a legacy of scientific innovation and inquiry that continues to influence the field of immunology.

7. Thomas Bartholin (1616–1680)

Thomas Bartholin, born on October 20, 1616, in a family renowned for its contributions to science and medicine, discovered the lymphatic system in humans, marking a significant advancement in medical research. His lineage, including his father, Caspar Bartholin the Elder, a prominent anatomist, and his brother and son, contributed substantially to anatomical science and medicine, establishing the Bartholin family’s legacy at the University of Copenhagen.

Educated at the University of Copenhagen, Bartholin distinguished himself in the medical field with his groundbreaking work on the lymphatic system and refrigeration anesthesia, demonstrating an innovative approach to medicine. His intellectual curiosity led him to explore various scientific disciplines, contributing significantly to understanding human physiology and anatomy. His work was widely recognized and respected, laying the groundwork for future medical discoveries.

Thomas Bartholin’s legacy is not only in his scientific discoveries but also in his contribution to medical literature, including his enhancement of his father’s anatomical work and research publications. His discoveries regarding the lymphatic system and refrigeration anesthesia have had a lasting impact on medical science, earning him a place among his time's most influential medical professionals. Bartholin’s death on December 4, 1680, marked the end of a remarkable career dedicated to advancing human knowledge in medicine.

8. Mogens Schou (1918–2005)

Mogens Schou, born in Copenhagen, Denmark, on November 24, 1918, embarked on a medical career influenced by his father, a prominent psychiatrist and medical director. Schou’s early exposure to psychiatric medicine at home steered him towards specializing in the study of manic-depressive illness, later known as bipolar disorder. He completed his medical degree at the University of Copenhagen in 1944, laying the foundation for his groundbreaking research in psychiatric treatment.

Schou’s professional journey was distinguished by his pioneering work in establishing lithium as a viable treatment for bipolar disorder. Inspired by John Cade’s findings on lithium’s antimanic properties, Schou conducted rigorous studies, including a double-blind placebo-controlled trial, which confirmed lithium’s efficacy. His collaboration with Poul Chr. Baastrup further demonstrated lithium’s prophylactic capabilities, challenging prevailing psychiatric norms and facing skepticism from peers. Despite resistance, Schou’s perseverance led to a landmark study published in The Lancet in 1970, conclusively proving lithium’s preventive benefits in managing bipolar disorder.

Throughout his career, Schou authored over 500 publications, contributing profoundly to psychiatric pharmacology and earning numerous accolades for his work with lithium, including the prestigious Albert Lasker Clinical Medical Research Award in 1987. His legacy is honored through awards named after him, acknowledging his lifetime achievements and significant contributions to bipolar disorder treatment. Schou’s dedication not only advanced psychiatric medication but also transformed the lives of countless individuals affected by bipolar disorder. He passed away on September 29, 2005, leaving a legacy of innovation and compassion in medical science.

9. Caspar Bartholin the Elder (1585–1629)

Caspar Bartholin the Elder, born on February 12, 1585, in Malmø, Denmark (now in Sweden), was a prodigious child, demonstrating remarkable intellectual abilities from a young age. His academic journey took him through prestigious European universities, where he was celebrated for his knowledge and eloquence in Greek and Latin orations. His early education set the stage for his later contributions to medicine and theology.

At the University of Copenhagen, where he was appointed professor of medicine in 1613, Bartholin made significant contributions to the field of anatomy. His textbook, “Anatomicae Institutiones Corporis Humani,” became a cornerstone of medical education for years, marking him as a pioneer in studying human anatomy. His discovery of the function of the olfactory nerve was groundbreaking, illustrating his dedication to advancing medical science.

Caspar Bartholin, the Elder’s legacy, is cemented in his scholarly achievements and familial lineage, with his sons and grandsons continuing his tradition of academic excellence. His death on July 13, 1629, marked the end of a luminous career that bridged the gap between medicine and theology, leaving a lasting impact on the scientific and medical communities.

10. Carl Lange (1834–1900)

Carl Georg Lange was born into affluence on December 4, 1834, in Vordingborg, Denmark, and embarked on his medical journey at the University of Copenhagen. Graduating in 1859, Lange was recognized for his academic excellence and potential. His early career focused on neurological and psychiatric disorders, laying the groundwork for his later contributions to psychology and the understanding of human emotions.

Lange’s seminal work, “On Emotions: A Psycho-Physiological Study” (1885), introduced a groundbreaking theory that emotions are physiological responses to external stimuli. This theory, developed concurrently with similar ideas by William James, became known as the James–Lange theory of emotion. Unlike James, Lange emphasized the role of vasomotor changes in the experience of emotions, a perspective that added depth to the psychological study of emotional states.

Beyond his work on emotions, Lange made significant strides in understanding mood disorders with his publication on periodic depression, what we now recognize as major depressive disorder. Despite his astute clinical observations and early advocacy for the use of lithium in treating mood disorders, his theories on uric acid’s role in depression were initially dismissed. Lange passed away on May 29, 1900, in Copenhagen, leaving behind a legacy marked by pioneering insights into the physiological basis of emotions and the nature of depressive illnesses.