Against the backdrop of increasing resistance rates of usual common antibiotics, also in dentistry, the bacterial spectra and resistograms of 173 odontogenic infections were analysed as part of a prospective study, under standardised conditions. The results were compared with those of a similar study, which was carried out at the clinical center of Martin-Luther-University thirteen years before. Further, it was investigated whether any differences between out- and in- patient treated can be found. The results showed a typical polymicrobial spectrum (a total of 593), isolated with a nearly 1:1 ratio between anaerobes and aerobes. No essential differences between out- and in- treated patients were found. An increase of the resistance rate was established for all tested antibiotics. This was especially significant for Clindamycin (8,6%). However, these resistance rates can currently still be regarded as low, from a regional perspective. Nevertheless, analogous analyses should further be carried out.