Introduction: For the last 30 years, the central pathomechanical path of periodontitis has been described as a polymicrobial infection by an oral biofilm containing specific pathogens. Consequently, a combination of microbiological tests followed by systemic antibiotics has been used as an adjunct to me-chanical removal of the biofilm. According to current knowledge, however, conversion of the originally physiological and symbiotic biofilm into a dysbiotic biofilm is crucial for the pathogenicity. Hence, testing for the presence of specific microorganisms is of less clinical relevance. Systemic administration of antibiotics after prior mechanical debridement undeniably has an added benefit in severe manifestations of periodontitis. In light of this, it is unclear how the decision to administer systemic antibiotics as part of peri-odontitis therapy is made in dental practices. Evaluating this decision process was the subject of this study. Methods: The preferences for prescribing adjunctive systemic antibiotics in periodontal therapy were determined with 29 question items using a web-based software (Unipark, Questback GmbH, Germany). The anonymous survey was advertised throughout Germany and conducted from May to October, 2018. Data organization, descriptive evaluation, and contingency analysis (Pearson's chi-squared test, Cramer's V) were performed with PASW Statistics 18 (SPSS Statistics 18, IBM, Chicago, USA). The significance level was defined as p = 0.05. Results: The online survey was accessed by 5745 interested persons. Of these, 425 (7.4 %) completed the survey in full. Most frequently, these respondents reported prescribing antibiotics in periodontitis treatment in patients with rapidly progressive (aggressive) periodontitis (34 %), with necrotizing ulcer-ative gingivitis/periodontitis with pronounced general symptoms (56 %) and with acute periodontal abscesses with tendency to spread or with pronounced general symptoms (76 %). 58 % of respondents started with the antibiotic therapy prior to root surface instrumentation and 28 % indicated using a microbiological test. The group of survey participants with a specialization reported more frequent use of national statements/guidelines compared to dentists without a specialization (90 % vs. 77 %). Discussion: According to the results, the majority of dentists participating in the survey used systemic antibiotics in periodontal therapy in a prudent and indication-related manner. However, this should not be generalized, since the study design with its unclear response rate is not sufficiently representative. Conclusion: The results suggest that the available recommendations from professional associations have largely been implemented. Palabras clave: antibiotics, guidelines, online survey, periodontitis