Introduction. Pericoronitis is an inflammatory and infectious condition that may accompany the eruption of teeth, especially the third molar, the microbial flora that develops in the distally located pseudopocket is the major etiological factor. This flora consists of obligate anaerobes, anaerobic and aerobic streptococci. Therapeutic management usually involves a combination of conservative and surgical treatment.Aim of the study. To establish the predominant microorganisms involved in the etiology of acute pericoronitis for a targeted antibiotic therapy. Materials and methods.. This explorative study was conducted in the Department of Oral and Maxillofacial Surgery and Oral Implantology „Arsenie Guțan” in collaboration with three private laboratories of medical investigations during October 2018 - December 2019. Pericoronal pockets of mandibular third molars from 23 patients showing symptoms of acute pericoronitis were sampled and subjected to microbiologic analysis. Results. In the majority of cases (15/23), the anaerobic flora predominated. Obligate anaerobes were present in 19 of the 23 samples. The bacteria most commonly detected were alphahemolytic streptococci (23/23), Prevotella (12/23), Veillonella (12/23). Amoxicillin and Cefixim were the most active in reducing the anaerobic cultivable counts. Besides obligate anaerobic bacteria, a predominantly pathogenic aerobic microflora was cultivated: Streptococcus viridans (78% of samples), Stomatococcus salivarius (71%), and Rothia dentocariosa (57%). Conclusions. These results highlight the diversity of the microflora associated with pericoronitis and their susceptibility can vary even within a species. As the anaerobic flora predominates, beta-lactame or any penicillins are highly recommended.