The bacteriotherapy started at the beginning of the 20th century. Paediatrics and gynecologists looked for therapeutical applications to take care of the survival of the newborns and the prosperity of the early infants, mothers included. There have to be mentioned persons like ESCHERICH and NISSLE for the Coli-therapy and DODERLEIN and MORO for the Acidophilus-application as well as TISSIER for the health importance of the anaerobic bifidobacteria. In the field of nutrition the microbiologist METCHNIKOFF initiated the use of fermented milk products for prophylactic purposes, e.g. for the prolongation of life. In the USA and in Europe these ideas were continuated by RETTGER, ORLA-JENSEN and HENNEBERG and many others. The idea for the propagation of such a natural therapy was the lack of enough substances being antagonistic against pathogenic and saprophytic microorganisms. With the detection and introduction of the synthetic chemotherapeutics and the antibiotics later on the importance of such a bacteriotherapy diminished. In the meantime as consequences of the widespread and overboarding application of chemotherapeutics and antibiotics an increase of resistance against therapeutic agents and of allergic reactions of the human population occurred. With the partial ban of such therapeutics, e. g. in animal nutrition, bacteriotherapy again gets greater importance. Now most of the preparations are called ,,Probiotics". Problems with the production and application of such preparations appeared unavoidable. Moreover, it seemed necessary to pay attention to some risks of those applications as well as to confirm the efficacy and the harmlessness of the cultures applied. Quality control and official approval of preparations should be achieved. Whether cultures of bacteria in foods should be regulated, has to be discussed. The ideas and the different ways of bacteriotherapies of past generations have had a real justification. They should be followed in the near future based on today's high standard of knowledge in microbiology and human nutrition.