Propolis is one of the few natural remedies that have maintained its popularity over a long period of time. The aim of this study is to investigate the antimicrobial properties of six propolis solutions and evaluate their cytotoxicity on gingival fibroblasts at different dilutions. Two different solutions of powder propolis (Sigma) and Turkish propolis were prepared and propylene glycol (PG) and alcohol were used as solvents for each propolis sample. In addition to the four propolis solutions, two other propolis samples of far geographic regions (USA and Australia) were included in the study. The antibacterial effects of six solutions on oral pathogen microorganisms were tested and their cytotoxic effects on human gingival fibroblasts were evaluated by MTT assay. The effective dilutions of the six propolis samples on periodontopathogen microorganisms were found to be cytotoxic to gingival fibroblasts. All solutions had strong antifungal activity and the effective dilutions were safe for gingival fibroblasts. Propolis could have a promising role in the future medicine, if appropriate solutions can be prepared being strongly antibacterial and non-cytotoxic as well. (c) 2005 Elsevier Ireland Ltd. All rights reserved.