Due to the emotional stress before the take off the lactoflora of 24 cosmonouts shows distinct changes regarding the spectrum of different species of Lactobacilli. Compared to long-time flights after short-time flights even stronger alterations are observed. The reason is that the disturbances which take place before the take-off as to the short space of time cannot be balanced by the macroorganism. Additionally, after a certain adaptive period the factors of the space travel begin to act. There are characteristic individual particularities regarding the number of Lactobacilli in the saliva and the feces of the cosmonouts.