OBJECTIVE: To evaluate the in vitro antimicrobial effectiveness of commercial herbal-based mouthrinses against oral microorganisms. METHODS: A total of three mouthrinses (OX, Pesona and Watsons) were tested for their antimicrobial activity against six oral organisms, Streptococcus mutans (S. mutans), Streptococcus sobrinus (S. sobrinus), Lactobacillus salivarius (L. salivarius), Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa) and Candida albicans (C. albicans) by standard agar-disk diffusion assay. Oradex mouthrinse containing 0.12% chlorhexidine gluconate and sterile distilled water was served as positive and negative controls, respectively. RESULTS: All mouthrinse formulations were effective in inhibiting the growth of S. mutans, S. sobrinus, L. salivarius and C. albicans. Among the tested mouthrinses, Pesona was the only effective mouthrinse against S. aureus and P. aeruginosa, similar to Oradex mouthrinse. Pesona mouthrinse formulation appears to be as effective as Oradex mouthrinse formulation to kill S. aureus and P. aeruginosa. Statistical analysis showed no significant difference among the tested formulations regarding their antimicrobial activities (P > 0.05). CONCLUSIONS: Pesona was not the only herbal mouthrinse effective in inhibiting the growth of S. mutans, S. sobrinus, L. salivarius and C. albicans in vitro. All tested formulations were effective against those strains. Our findings may serve as a guide for selecting a kind of herbal mouthrinses as well as providing information to the dental professionals about the efficacy of these products.