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Paul Ehrlich Biography, Research, Idea of Magic Bullet

Paul Ehrlich was a German scientist and physician who worked in the fields of immunology, hematology, and antimicrobial therapy. One of his notable achievements is the cure for syphilis and discovering the gram staining technique. After learning the staining techniques, it was possible to differentiate between different types of blood cells and also aid in diagnosing several blood diseases. Ehrlich was also the pioneer of working in hematology and immunology.

Ehrlich prepared arsphenamine in the laboratory, the first effective drug in treating syphilis, and introduced the concept of chemotherapy. He introduced the idea of a magic bullet. He contributed to the development of antiserums to cure diphtheria. Ehrlich was awarded Nobel Prize in Physiology or Medicine for his notable work in immunology in 1908. Ehrlich founded and directed a German institution and medical regulatory body for vaccines and medicines, Paul Ehrlich Institute.

Birth14 March 1854
Birth NamePaul Ehrlich
Birth PlaceStrehlen, Lower Silesia, Poland
Famous ForChemotherapy, Microbiology, Immunology, Basophils, Mast Cell, Magic Bullet,  Paul Ehrlich side Chain Theory, Recpetor Theory, Ehrlich’s reagent
SpouseHedwig Pinkus
Children2, Stephanie and Marianne
Notable StudentHans Otto Friedrich Schlossberger
Death20 August 1915
Resting PlaceBad Homburg, Hesse, German Empire

Early Life:

Paul Ehrlich was born in Strehlen, Lower Silesia, Poland, on 14 March 1854. His father, Ismar Ehlrich,  was a distiller of liqueurs, innkeeper, and the royal lottery collector in Strehlen, a town of 5,000 inhabitants. His grandfather, Heymann Ehrlich, was a moderately successful distiller and tavern manager. Ehrlich was the second child of his parents.

Personal Life:

Ehrlich married Hedwig Pinkus in 1883 in the synagogue in Neustadt. They had two daughters, Stephanie and Marianne. Hedwig was the sister of Max Pinkus, who owned the textile factory in Neustadt.


After attending elementary school, Paul enrolled in the time-honored secondary school Maria-Magdalenen-Gymnasium in Breslau. He became fascinated by staining microscopic tissue substances in the school. Paul retained his interest in staining techniques during his t medical studies at the universities of Wroclaw, Strasbourg, Freiburg im Bresigau and Leipzig. After obtaining his doctoral degree in 1882, he worked at the Charite in Berlin as an assistant medical director under Theodor Frerichs. He founded experimental clinical medicine, focusing on hematology, histology, and color chemistry.

After completing his clinical education at the well-known Charite medical school and teaching hospital in Berlin in 1886, Paul traveled to many countries in 1888 and 1889 to cure a case of tuberculosis that he had contracted while working in the laboratory. After this tour, he established a private medical practice and small laboratory in Berlin-Steglitz.  In 1891, Robert Koch, the presenter of Germ Theory of Diseases, invited him to join them at his Berlin Institute of Infectious Diseases.

His institute moved to Frankfurt am Main in 1899 and was named the Institute of Experimental Therapy. In 1904, Paul received the position of honorary professor at the Univesity Of Gottingen. In 1906 Ehrlich became the director of a private research foundation affiliated with his institute,

Georg Speyer House, in Frankfurt. Paul discovered the first drug targeted against a specific pathogen in 1909.



In the early 1870s, Karl Weigert was the first to stain bacteria with dyes and initiate aniline stains for histological studies and bacterial diagnostics. He was the cousin of Paul Ehrlich. Ehrlich continued the research on pigments and staining tissues for microscopic examination started by his cousin during his studies in Strasburg. He spent his eighth semester in Freiburg im Breisgau investigating the red dye dahlia that led to his first publication.

Paul ehrlich researh lab

Paul Ehrlich Discovery Of Blood Cells:

One of the most remarkable results of his experiments was the discovery of a new cell type. Ehrlich discovered in the cytoplasm of plasma cells a granulate material that could be noticed with the help of an alkaline pigment. He thought this granulate was a symptom of good nutrition and named their mast cells accordingly. By studying the presence of granules, Paul could differentiate between mono- and poly-nuclear leucocytes, nongranular lymphocytes, mast cells, and eosinophils granulocyte. In 1880, he discovered red blood cells. He illustrated the existence of nucleated red blood cells, which he classified into normoblasts, microblast, megaloblasts, and poikiloblasts, all precursors of erythrocytes. Ehrlich thus laid the basis for analyzing different kinds of anemias after creating the foundation for systematizing leukemias with his experimentation of white blood cells. In 1881 he published a new urine test that could differentiate different types of typhoid fever from simple cases of diarrhea. The intensity of staining made disease diagnosis easy. The pigment solution he used in this procedure today is Ehrlich’s reagent.

Work On Immunology:

Ehrlich started his first experiments on immunization in his private laboratory. He accustomed mice to the poisons abrin and ricin. After providing food to them with small but increasing dosages of ricin, he made sure that they had become “ricin-proof.” Ehrlich elucidated this as an immunization technique and observed that it abruptly started after a few days and still existed after several months. However, mice immunized against ricin were also sensitive to abrin as untreated animals. This was followed by working on the inheritance of acquired immunity. It was already described that in some cases, after smallpox or syphilis infection,  immunity was transmitted from the parents to their offspring.  Ehrlich refused the concept of inheritance in the genetic sense because the product of a male mouse immunized against abrin and a female mouse were not immune to the abrin.

Ehrlich’s Side-Chain Theory:

According to Paul Ehrlich theory,  cell cytoplasm contains unique structures with chemical side chains to which the different toxin binds, affecting function. If the creature survives the effects of the poison, the blocked side chains are renewed. This renewal can be trained, the name for this phenomenon being immunization. If the cell produces excess side chains, these might also be entered into the blood as antibodies. For providing a theoretical basis for immunology and his work on serum valency, Ehrlich received the Nobel Prize for Physiology or Medicine in 1908 with Élie Metchnikoff.

Cancer Research:

Ehrlich had also received a personal request from the German Emperor Wilhelm II to devote all his energy to cancer research. Such efforts led to the formation of a department for cancer research associated with the Institute of Experimental Therapy. The chemist Gustav and his colleagues worked in this institute. Ehrlich informed his sponsors that cancer research requires basic research and that cancer treatment was not expected very soon.

Among the results received by Ehrlich and his fellow researchers was the perception that when tumors are grown by transplanting tumor cells, their malignancy increases from generation to generation. If the primary tumor is removed, then the spread of cancer increases. Ehrlich applied bacteriological methods to cancer research.


Before the Institute of Experimental Therapy moved to Frankfurt, Ehrlich had already started work on methylene blue. After the death of Georg Speyer, his widow Franziska Speyer endowed the Georg-Speyer House in his memory, which was next door to Ehrlich’s institute. As director of the Georg-Speyer House, Ehrlich had done his chemotherapeutic research there. Paul was looking for an agent that was as effective as methylene blue but should not have side effects. His model was o, the impact of quinine on malaria. On the other hand, similar to serum therapy, he thought there must also be a pharmaceutical chemical that would have a specific effect on individual diseases. His goal was to find a “Therapia sterilisans magna,” in other words, a treatment that could kill all disease-causing agents.

Magic Bullet:

Paul explained that if a compound could be made specifically targeting a pathogenic organism, then a toxin for that organism could be delivered along with the target agent. Hence, a Magic Bullet would be formed that killed only the organism targeted. The concept of a “magic bullet” has to some extent, been realized by the development of drug-antibody conjugates, as they enable cytotoxic drugs to be selectively delivered to their designated targets.


In 1915, Paul Ehrlich went to Bad Homburg for a holiday. The cause of death was a heart attack on August 17 of that year, and died on August 20, 1915. He was buried at the Old Jewish Cemetry, Frankfurt.

Read Also: James Watson Biography


  • In 1882, he was awarded the title of Professor.
  • In 1890, Paul was appointed Extraordinary Professor at the Friedrich-Wilhelms-Universität.
  • In 1896, Ehrlich was Given the nonacademic Prussian title of a Medical Councillor.
  • In 1903, he was awarded Prussia’s highest distinction in science, the Great Golden Medal of Science
  • In 1907, he was Granted the seldom-awarded title of Senior Medical Councillor.
  • In 1908, he received The Nobel Prize in Physiology or Medicine for his “work on immunity.
  • In 1912, he was made an honorary citizen of Frankfurt A.M. and his birthplace Strehlen.
  • In 1914, he was appointed full Professor of Pharmacology at the newly established Frankfurt University.


  • What is Paul Ehrlich best known for?

Paul Ehrlich is best known for his significant contributions to immunology, medicine, particularly in chemotherapy. He is considered one of the pioneers in these fields and is widely recognized for his groundbreaking work on understanding the immune system and developing new treatments for diseases.

  • What happened to Paul Ehrlich?

Paul Ehrlich passed away on August 20, 1915, in Bad Homburg, Germany. He lived a life dedicated to scientific research and made remarkable contributions to medicine during his career.

  • What is the background of Paul Ehrlich?

Paul Ehrlich was born on March 14, 1854, in Strehlen, in what is now Poland. He studied medicine at the University of Breslau and later pursued his doctorate at the University of Leipzig. Ehrlich went on to become a prominent scientist and physician, leaving a lasting impact on the medical field.

  • What did Paul Ehrlich find?

Paul Ehrlich made several important discoveries throughout his career. One of his notable findings was the identification of specific chemicals that could selectively target and kill disease-causing microorganisms without harming healthy cells. This laid the foundation for the development of chemotherapy as a treatment for various diseases.

  • What is the Ehrlich theory?

The Ehrlich theory, also known as the “side-chain theory,” proposed by Paul Ehrlich, explained the interaction between antigens and antibodies in the immune system. According to this theory, the immune response involves the binding of antigens (foreign substances) to specific receptors on the surface of immune cells, triggering a defense mechanism to eliminate the invader.

  • What is Paul Ehrlich’s magic bullet?

Paul Ehrlich coined the term “magic bullet” to describe his concept of a specific chemical compound that could selectively target and destroy disease-causing microorganisms. He envisioned a drug that would act as a precise weapon against pathogens while sparing healthy cells, effectively treating diseases without causing excessive side effects.

  • Did Paul Ehrlich invent chemotherapy?

While Paul Ehrlich did not invent chemotherapy in its entirety, he played a pivotal role in its development. Ehrlich’s research and experiments on chemical compounds led to the discovery of certain drugs, such as Salvarsan, which became the first effective cure for syphilis. His work laid the groundwork for the development of modern chemotherapy approaches.

  • Did Ehrlich win a Nobel Prize?

Yes, Paul Ehrlich was awarded the Nobel Prize in Physiology or Medicine in 1908. He received this prestigious honor for his groundbreaking contributions to immunology, specifically for his discoveries related to the immune response, including his work on the side-chain theory and his research on the treatment of diseases.

  • What did Ehrlich do to cure syphilis?

Paul Ehrlich developed a drug called Salvarsan, also known as “606,” as a treatment for syphilis. Salvarsan was the first effective treatment for this sexually transmitted infection. Ehrlich’s research on chemical compounds led to the discovery of this arsenic-based drug, which proved to be a significant advancement in the medical treatment of syphilis.

  • What does Ehrlich mean?

“Ehrlich” is a German surname that originated from the German word “ehrlich,” meaning “honest”

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