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Professor Dr. Gunther Enderlein was born July 7th, 1872 in Leipzig, located in eastern Germany. Enderlein is often called the founder of isopathic medicine, though the work of Johan Joseph Wilhelm Lux and Antoine Bechamp does proceed. He was born into a family of teachers and developed early an avid interest in science. He studied natural science, physics, and zoology at the University of Liepzig and specialized in entomology. He graduated in 1889, summa cum laude, with a PhD zoology. 

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Early Years 1872 to 1937


In 1889, following graduation, he worked as assistant at the Museum für Naturkunde in Berlin, department of Zoology. 

In October 1900 Enderlein became an assistant at the Zoological Museum in Berlin (administration of Hymenoptera and Myriapods for a monthly salary of 100 marks.)

He married in 1904 and in July of 1906, he and his first wife moved to Szczecin, now in Poland. There Enderlein became curator at the Stiidtisches Museum in Stettin. 

In 1912, he became head of the Zoological Museum in Berlin department.

In 1914, the First World War began and Enderlein enlisted as a doctor in a German Military Hospital in Stettin. He primarily served the military as a surgeon major even though he was a zoologist, as there were not enough physicians available at that time.


He returned to Berlin in 1919 and remained there until 1937. 

April 1, 1919, he became the "Curator for Diptera and lower Insects" and administrator of the ‘central office for blood-sucking insects’ at the Zoological Museum der Universitat Berlin.

His first wife died in 1920 and he remarried in 1937. During his life he was blessed with children, grandchildren, and great grandchildren. 

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From 1916-1922, Enderlein conducted groundbreaking research on his theory of bacterial life cycles and published his findings in a book entitled Bakterien Cyklogenie (The Life Cycle of Bacteria) in 1925. Owing to the prevailing conditions resulting from the war, his monograph on this subject was only published in 1925. As he was describing morphological facts that had previously been unknown to microbiology, he developed a whole new terminology; however, this resulted in the procedures he described being difficult to understand. 

Bear in mind that Professor Enderlein conducted his microbiology studies approximately 100 years ago. This was the beginning era of chemistry and electrical innovation. Beyond optical microscopic methods and rudimentary laboratory procedures, there were not any other instruments available that would have made it possible to do microbiological/genetic research as we are capable of today. At that time microscopy using the optical mode of darkfield was standard equipment in any university microbiological laboratory. With only darkfield microscopy at that time it is amazing what researchers like Enderlein were able to discover.

Professor Enderlein showed that the patient's inner milieu is principally responsible for the development of degenerative and microbial diseases. Most infectious and bacterial diseases can therefore be countered by changing this milieu in the direction of normal homeostasis. The "milieu" is determined in part by the acid-base balance, by the protein content of the organism, excessive protein of animal origin, and the content of minerals and nutrient elements. The over-acidification of the organism (tissue hyperacidity) is the result of the long-standing, mostly protein-heavy malnutrition, as well as the increasing depletion of base-trace elements and minerals (chromium / zinc / manganese / selenium / magnesium / potassium / calcium, etc.). Through proper nutrition and the replacement of missing nutrient elements, as well as by supplying base equivalents and isopathic active remedies, the inner milieu can be improved in such a way that chronic diseases can be influenced and regressed.

Another significant finding of Professor Enderlein was that there is a symbiosis of microorganism in the human and animal body which he termed ‘endobionts’. The modern term coined by Prof. Max Taylor of the University of British Columbia, Vancouver, Canada, is "serial endosymbiont theory" (SET). The genesis of this new term and the correlations are described in the recommendable and descriptive book "Symbiotic Planet - A New Look at Evolution" by Prof. Lynn Margulis (Perseus Books, 2000). SET claims that unicellular organisms, plants, fungi, animals, and humans are the product of a symbiogenesis. This is a formation of new organs and organisms by symbiotic fusion of at least two to four life forms.

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Professor Enderlein published more than 500 scientific articles, mostly about insects. In May of 1924 he was conferred the appointment as ‘Professor’ and retired from that appointment in 1937 during the trouble years Nazi rise to power.

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In 1916, Professor Enderlein published an article about spotted fever, a bacterial disease (Rickettsia) spread by ticks. During that period, he also was the director at the Zoological Institute and curator at the Berlin Zoological Museum. 

The Middle Years         1937 to 1949

Throughout his life Enderlein continued to work extensively in taxonomy and systematics of many Diptera families. Diptera is a large order containing an estimated 1,000,000 species including horseflies, crane flies, hoverflies and others, although only about 125,000 species have been described. Many insects were named by him and some still carry his name. Enderlein was mostly interested in the fly family, Simuliidae of the Culicomorpha infraorder, and named many new fly taxa. The early phase of entomology, particularly Coniopterygidae or ‘dustywings’ research, was characterized by much uncertainty in the identification of the species. Through using the structures of the genital segments as taxonomic criteria for the first time, Enderlein introduced a completely new taxonomy phase. He is undisputedly the father of modern Coniopterygidae research.

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Bacterial Cyclogeny

In addition to groundbreaking entomology research, Professor Enderlein spent most of his long-life studying organisms in live blood via darkfield microscopy. He observed that blood is not sterile, and that microorganisms appear in various developmental stages and in diverse forms. He concluded that the monomorphic perspective of disease conditions favored by Louis Pasteur and others could no longer be maintained and that a pleomorphic perspective more accurately reflected the disease process. The term pleomorphism comes from the Greek pleion = more, morphe = form, and was in part developed by French chemist and biologist Antoine Béchamp (1816–1908). Similar concepts were known in ancient times as concepts of ‘abiogenesis’. Without a doubt, Enderlein’s research of pleomorphism of microorganisms has been most controversial for decades. Even today most conventional teaching still holds the view of two centuries ago that microorganisms can only exist in unchangeable forms. 


Based on his own life long extensive microscopic observations of live blood and the early work of Antoine Béchamp, an opponent of Louis Pasteur, and other contemporaries such as Wilhelm von Brehmer and Johan Joseph Wilhelm Lux, Enderlein developed his own complicated pleomorphism hypothesis. He observed that certain microorganisms would pass through a particular development cycle that he called cyclode (bacterial cyclogeny). Béchamp had proposed earlier the opinion that in every animal or plant cell there were small particles that he called microcymas (microzymas), which did not perish after death of the organism itself and that other microorganisms could develop from them. These microcymas were thought to be in each living being, in humans, animals and plants, to be eternal and indestructible and to constitute the transition between non-living and living matter.  They were also thought capable of transforming into pathogenic bacteria under certain corrupted milieu circumstances. Enderlein later renamed these small particles or protein grains "protits". Modern microbiological thinking classifies the structures termed protits by Enderlein as probably being "nanobacteria". Nanobacteria were discovered by the Fin Olavi Kajander, University of Kuopio, only about 20 years ago.


Ciftcioglu, Neva, Ilpo Kuronen, K. Åkerman, Erkki Hiltunen, Jukka Laukkanen, and E. Olavi Kajander. "A new potential threat in antigen and antibody products: nanobacteria." Vaccines (1997): 99-104.


The term “cyclogeny” describes the changes and the journey of pathogenic and non-pathogenic micro-organisms through all phases (“valencies”). According to Enderlein the cycle starts below the limits of microscopic visibility, the viral sphere, then on via forms of higher valency like cocci and bacilli, to culminate in the fungal phases. The bacterial nucleus (“mych”) has a special significance. Although this was already known before Enderlein, its function had not been interpreted accurately. According to the “basic Anatartic Law” formulated by Enderlein, the increase in valency of the microbe depends on the “milieu” that is present in blood and tissues, which is mainly characterized by its pH value. Bacteria can either multiply asexually by division or branching (“auxanogeny”) or sexually after prior fusion of cell nuclei (“probænogeny”). Sexual multiplication is essential for movement to a higher or lower phase. 40 years after Enderlein’s discovery, the Nobel prize was awarded to Lederberg in 1958 for discovery of “polymorphy” and sexual multiplication of bacteria by the fusion of cell nuclei.

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Hypothetical separation of the Aspergillus niger cyclode from that of Mucor racemosus
(Arnoul, F.: Der Schlüssel des Lebens – Heilung durch biologische Therapie nach Professor Dr. Enderlein (The key of life - Healing through the natural therapy according to Professor Dr. Enderlein), Reichl, 1998.; Rau, Th.: Isopathie: Milieukorrektur und Sanum-Therapie (Isopathy: Milieu adjustment and Sanum-Therapy)

At that time Enderlein, it was also known that plasmodia (the causal agents of malaria) were able to change form during their different developmental stages. Thus, the primary themes of Enderlein’s research were pleomorphism, symbiosis and the cyclogeny of microorganisms, particularly as it occurs in human and animal bodies, determining whether there is disease or health.


According to Enderlein, different diseases are related to cyclodes leading to particular microorganisms. He was mainly interested in two cyclodes: the cyclode leading to the fungus Mucor racemosus, and the cyclode leading to the fungus Aspergillus niger. Thus, apart from naming the various phases in the development of micro-organisms, Enderlein also succeeded in proving the existence of the most important symbiont (“endobiont”) in warm-blooded creatures. He discovered Mucor racemosus Fresen(ius) 1870, in all its developmental stages. In the low valency stages, the endobiont lives as a physiological regulator; in the higher valency stages it will develop pathogenic characteristics, depending on the environment (or milieu) that surrounds it. Changes in the environment which are followed by an endobiosis occur in all chronic illnesses. The endobiosis caused by Mucor racemosus in a higher-valency form is characterized by congestive symptoms (e.g. diseases of the blood and venous system, wounds, hearing loss and neurodermatitis). Thus, with the aid of dark field microscopy applied to native blood samples, he was able to demonstrate this vital microbial process, in terms of both its origin and its cycle.

The Mucor racemosus cyclode leads to diseases of circulation. In these cases, Enderlein found that a ‘marcant filit net’ is present in live blood -darkfield analysis. Enderlein also discovered that dosage of low valence Mucor racemosus symbionts help correct the circulatory stagnancy, as they are able to destroy greater valent microorganisms. This discovery was a major development in isopathic medicine. Thus, Enderlein found that the pathogenic higher-valency phases of the endobiont could be reconverted into a non-pathogenic phase by introducing low-valency forms while simultaneously treating the milieu (“isopathic therapy”). These processes can be observed with the help of dark-field microscopy of live blood. 

The causative agent of the second electively pathogenic endobiosis which, in contrast to the Mucor symbiosis, is non-physiological, was identified by Enderlein as the mold Aspergillus niger van Tieghem. In its polymorphy and phase-dependent pathology this he believed to be a potential causative agent of cancer and tuberculosis. Vaudremer (1921) and Tissot (1925) had already found a genetic connection between the tubercle bacillus and fungi of the species Aspergillus (according to Enderlein, 1949).

Vaudremer, Albert. "Un bacille tuberculeux humain, un bacille tuberculeux bovin acidorésistants facultatifs." Compt. rend. Soc de biol 84 (1921): 259.


The higher and high valency phases of Aspergillus niger are closely connected with calcium metabolism and cell respiration (citric acid cycle) and they cause chronic tubercular diseases in warm blooded creatures “to the right of the biological incision” (See Reckeweg homotoxicology). Examples are chronically relapsing susceptibility to infections, tuberculosis, paratuberculosis, asthma, arthrosis, ankylosing spondylitis, cysts, ovarian and prostate diseases, as well as cancer. Among the tubercular symptoms, degenerative diseases such as auto-immune disorders may also be found. Also, in this case, the isopathic introduction lower valence Aspergillus symbionts was proven helpful for restoring a normal cyclogeny.

Thus, with isopathic remedies Enderlein observed that pathogenic bacteria and fungi may regress or downgrade back to harmless particles, but this process is only possible in a healthy host organism – with a healthy milieu or biological terrain. As early as 1916, Dr. Enderlein discovered that primitive microorganic forms prepared in a remedy, when combined with a change in the biological terrain (or milieu) of the body, can cause virulent forms to return to their original avirulent condition, bringing healing to the host body.


In short, Professor Enderlein stated that there are always microorganisms in the blood plasma as well in the different blood cells and that these microorganisms can be divided into a number of different types, which he meticulously identified. He also believed that these microorganisms would always exist as one essential part of the life process. They are not only able to divide but can also develop through special stages of development, each with modified properties. Thus, Enderlein was one of the first proponents of the pleomorphic theory within microbiology. According to Enderlein, these microorganisms spend the earliest stages of development in a mutually beneficial relationship with the tissue cells in ‘somatic ecology’ - this is the so-called symbiosis stage. As the biological terrain become more acid and toxic these organisms can attack the cells of various tissues, and this is known as the so-called dysbiosis stage. 

Enderlein’s view of the special importance of the two fungi Mucor racemosus and Aspergillus niger has not yet been sufficiently confirmed by today’s microbiological research. However, researchers have arrived at similar conclusions as Enderlein did, based on their own research. An extensive survey of the numerous studies on polymorphic “symbionts”, particularly in German speaking countries, was carried out by Windstosser and others.

Windstosser, K.K.: Polymorphe Symbionten in Blut und Körpergewebe als potentielle Kofaktoren des Krebsgeschehens (Polymorphic symbionts in blood and body tissues as potential co-factors in carcinogenesis) Semmelweis, 1995.

Richard McLaughlin "Naturally-occurring Pleomorphic Microorganisms in Human Blood" published in "Pleomorphic Microbes in Health and Disease", Holger N.I.S., Inc., 1999.

In English-speaking countries too, intensive research on the pathogenicity of polymorphic forms of microbes has been carried out during the last 40 years. Probably because of the language barrier, the results of earlier research remained unnoticed. Only in recent times has an effort been made by Canadian research groups to pool this knowledge.

(First International Symposium on Pleomorphic Microbes in Health and Disease, 18th-19th June 1999, Montreal, Canada).

The existing investigations on the properties and pathogenicity of the so called “Cell Wall Deficient Forms” (CWD) were recently summarized by Lida H. Mattman, Emeritus Professor of Microbiology at Wayne State University, Detroit, Michigan.

Mattman, L. H.: Cell Wall Deficient Forms – Stealth Pathogens, 2nd edition, CRC Press, 1993.


Cell Wall Deficient Forms is now used as the umbrella term for synonyms like “L-forms”, “L-phases” or “spheroplasts” that can be found in the hematological literature. CWD also covers the previously used term “protoplast”. 

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History of Sanum Isopathic Remedies


Using his knowledge of these specific microorganisms, Professor Enderlein developed homeopathic and isopathic remedies from their low valenced fungal cultures. When these living remedies contact virulent microbial masses, the masses are induced to return to their avirulent form, and then leave the body through the natural organs of elimination. To achieve this end, Enderlein became the production manager for the company Sanum. It was formed in 1932 by an employee of the Robert Koch Institute to manufacture isopathic remedies for immunobiological health. In 1944 he founded his own pharmaceutical company IBICA in Berlin. In 1949, he moved the company's headquarters and production facilities to Aumuehle, near Hamburg. He was also the publisher of a newspaper called Akmon


Professor Enderlein with Mr. Heinrich Kehlbeck


Professor Enderlein’s close confidant for many decades, Mr. Heinrich Kehlbeck, bought Sanum with all its rights and trademarks in 1975. He merged with the IBICA Institute to create Sanum-Kehlbeck GmbH & Co. KG. Enderlein gave the Kehlbeck family exclusive custodianship of all his original microbial cultures, his specialized production knowledge, and sole rights to use his work. After his death, IBICA and Sanum merged in 1975 to form the Sanum-Kehlbeck company which is still active today. Sanum-Kehlbeck still retains the official registrations for these original products. All of Sanum’s products are produced at their excellent manufacturing facility to GMP standards and they comply with EU legislation.

Professor Enderlein was an honorary member of the "Societas pro fauna et flora fennica" in Helsingfors (since 1920), the "Microbiological Society" in Vienna (since 1926)and the "Liga Argentina pro estudio e investigacion de virus y tumores" (since 1968). During his long life he was awarded and honored with countless dedications.

Death and Legacy

On August 11th, 1968, Enderlein died in Wentdorf near Hamburg at the age of 96 from injuries suffered from being hit by a truck. In 1975, the equipment of the IBICA Company was sold. 


Microbial Life
in Blood

Because Enderlein wrote all his publications (more than 500) in German,  much of his important work has until now been almost completely unknown outside German-speaking countries. Another important reason why Enderlein’s work has been historically overlooked may be because within the conventional medical paradigm it is considered a priori that the blood is sterile. This erroneous view has continued to dominate the thinking within orthodox medicine, and this hinders research into the possibilities of microbial life in the blood.


Professor Enderlein was a visionary, courageous thinker, and a meticulous researcher who made profound discoveries about the nature of chronic disease during his 60-year career. Enderlein devoted most his life entrenched in scientific research proving his pleomorphic thesis and discovering unique homeopathic and isopathic remedies that rose from it. Enderlein was undoubtably a genius, and a brilliant one. Though he is better known for his controversial discoveries in bacteriology, he never gave up his passion for studying insects. His name will always have a permanent residence with a certain group of insects. Professor Enderlein was an important pioneer on the frontier of microbiology and connected this field to clinical bioregulatory medicine.

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Professor Enderlein’s research was recently summarized in English by Dr. Maria-M. Bleker (Blood Examination in Darkfield, Semmelweis-Verlag, Hoya, Germany, 1993, ISBN 3-925524-01-0). It is to be hoped that the results of Enderlein’s research will now get the attention they deserve.


Important Works of Professor Gunther Enderlein

  • Enderlein, G.: Bakterien-Cyclogenie. Prolegomena zu Untersuchungen ueber Bau, geschlechtliche und ungeschlechtliche Fortpflanzung und Entwicklung der Bakterien (Cyclogeny of Bacteria. Prolegomena to a study of the structure, sexual and asexual reproduction and development of bacteria), Walter de Gruyter & Co, Berlin, 1925; reprint edition 1981 published by Semmelweis.

  • Gunther Enderlein, Bacteria cyclogeny: Prolegomena to a study of the structure, sexual and asexual reproduction and development of bacteria, Enderlein Enterprises (1981), ASIN: B00073C4IQ

  • Enderlein, G.: Über die potenzierte Vaccinebehandlung der Tuberkulose (On the treatment of tuberculosis with potentised vaccines), Immunobiologica 1 (2), 33-36, 1949

  • Enderlein, G.: Der Terminus Virus kein vergleichend-morphologischer Begriff (The term “virus” – not a comparative-morphological concept), Immunobiologica 1 (5/6), 188-192, 1954

  • Enderlein, G.: Akmon - Bausteine zur Vollgesundheit und Akmosophie, Bd. I-III, Ibica, 1955, 1957, 1959

  • Enderlein Günther, Some new pathogens from the relationship of the diphtheria pathogen , meeting reports of the Society of Friends of Nature Research in Berlin. Born in 1916: (395-400).


Parts of this biography have been added from the research and presentations of Dr. Peter Schneider and Dr. Thomas Rau: 

Schneider, Peter. "Prof. Enderlein's Research in Today's View." Semmelweis-Institut (2001): 17.

Schneider, Peter. "Enderlein's microbiological theory."

Rau, Th.: Isopathie: Milieukorrektur und SANUM-Therapie (Isopathy: Milieu adjustment and SANUM-Therap


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