With mechanical cleaning, it is never possible to remove all bacteria from tooth surfaces, in, for example, furcation sites and at the bottom of the pocket. Supporting non-surgical periodontal treatment with the use of antimicrobial agents is, therefore, an obvious approach in order to achieve a better treatment outcome.. The combination of amoxicillin and metronidazole has been thoroughly investigated as a support in periodontal treatment and deserves a place among the tools the dental care professional has for effective treatment. However, there is at present no strict indication in which clinical situations antibiotics can be successfully prescribed. Considering responsible use of antimicrobials by healthcare professionals (antimicrobial stewardship) the decision to support periodontal treatment with antibiotics should be in the hands of those authorised to provide a prescription. Additional rinsing with chlorhexidine twice daily during periodontal treatment and the subsequent two weeks (6-8 weeks) can be considered in order to enhance the effect of clinical treatment.