To assess the activity of different mouthrinse solutions compared to sterile water and sage tea against aerobe bacteria in the oral cavity. The extent and the duration of the salivary bacterial count reduction were determined using a uniform model that allows a direct comparison of the different products. In contrast to previous investigations the antimicrobial activity of the tested products was stopped by specific neutralizers immediately after sampling. The obtained results allowed us to classify four categories of mouthrinse solutions according to their antimicrobial properties: Products without any active antimicrobial effect (sterile water, sage tea, Fluomint-Lysoform), products with a weak and temporary effect that does not exceed a salivary bacterial count reduction of 1.5 log of colony forming units (cfu) immediately and 1.0 log cfu 1 h after application (hydrogen peroxide, Meridol, Listerine, Lavasept), products with a strong immediate effect (> or =1.5 log cfu) but no prolonged activity (Betaisodona solution, acriflavine) and finally products that exert a sustained effect of at least 1.0 log cfu 1 h after application (Chloramine T, Gurfix, Skinsept mucosa, Corsodyl, Dobendan, Octenisept). The method used in this investigation allows an easy and reproducible evaluation of antimicrobial efficacy and may be part of a future test guideline for efficacy testing of antiseptics.