Günther Enderlein (7 July 1872 – 11 August 1968) was a German zoologist, entomologist, microbiologist, researcher, physician for 60 years, and later a manufacturer of pharmaceutical products.

Enderlein received international renown for his insect research, and in Germany became famous due to his concept of the pleomorphism of microorganisms and his hypotheses about the origins of cancer, based on the work of other scientists.

First he worked as assistant at the Museum für Naturkunde in Berlin, and went later to Stettin, now Szczecin in Poland but at that time in Germany.

After his death, IBICA and Sanum merged in 1975 to form the Sanum-Kehlbeck company which is still active today.

He worked in taxonomy and systematics of many Diptera families, as well as Psocoptera (of which he described the genera Prionoglaris and Trichadenotecnum).

His way of distinction by external characteristics led to some disputes inside the scientific community of that time (see Zwick 1995 for details).

The term pleomorphism comes from the Greek pleion = more, morphe = form, and was apparently created by French chemist and biologist Antoine Béchamp (1816–1908).

Béchamp had issued earlier the opinion that in every animal or plant cell there were small particles that he called microzymas or granulations moleculaires.

At that time, it was also known that plasmodia (the causal agents of malaria) were able to change form during their different developmental stages.

He stated that small, harmless, beneficial herbal particles were present in every animal or plant which may transform into larger pathogenic bacteria or fungi under certain circumstances.

A disturbance of the symbiotic, friendly coexistence between the smaller particles and the larger organism would start a dangerous situation he called mochlosis that leads at the end to a disease, facilitated by a wrong way of thinking and living.

If this process continues, we will observe larger particles called mychits, or bacteria-nuclei, forming the basis of a bacterium.

He claimed that bacteria and fungi may regress or downgrade back to harmless particles, but this process is only possible in a healthy host organism.