Ficus benghalensis, commonly known as the banyan, banyan fig and they belong to the family monsaceae. Around 750 species of plants occurring in tropical and subtropical forests belong to the genus Ficus. These have been found to possess medicinal properties. Stevia also known as stevia rebaudiana belongs to the family Chrysanthemum. This plant was called caá-êhê, meaning “sweet herb” by Guarani Indians of the Paraguayan highlands as they are nonnutritive sweeteners. The main aim is to study the Antimicrobial and cytotoxic effect of herbal mouthwash prepared using ethanolic extract of Ficus benghalensis and stevia. 0.5g stevia and 0.5g Ficus benghalensis plant extract powder was measured and transferred into the conical flask. Mouthwash was prepared using ethanolic extract of stevia and Ficus benghalensis and the cytotoxicity and anti microbial activity was determined. Inorder to determine whether the prepared bioactive compound is toxic to cells, evaluation of cytotoxicity is useful which is done using hatched nauplii. A clean ELISA plate was taken and the wells were marked with the concentration of 5μl, 10μl, 20μl, 40μl, 80μl, control respectively. Each well was filled with 3ml of salt water and 10 hatched nauplii or brine shrimp were collected and added to the wells. Mouthwash was pipetted with respective concentration into the wells with nauplii and kept for 24hrs. To analyse the toxicity of ethanol extract mouthwash, the count of nauplii was taken after 24 hrs excluding the dead nauplius. The mueller Hinton agar and nutrient broth were purchased from Hi-media, India. By agar well-diffusion method, the antimicrobial activity of prepared stevia and Ficus benghalensis ethanol extract based mouthwash was tested. Pathogenic isolates S.mutans and Lactobacillus were the culture used for bactericidal activity. Three different concentrations (25μl, 50μl, 100μl) of mouthwash solution were poured into each well on plates using sterile micropipette and were kept in an incubator at 37 degree Celsius for 24hrs. The bacterial zone of inhibition was observed and measured after incubation. Cytotoxicity and anti microbial activity was determined. As the concentration increased the cytotoxicity of the herbal mouthwash prepared using ethanolic extract increased. The highest percentage of death of nauplii was at 80 µl concentration of ethanolic extract mouthwash. As the concentration of the mouthwash increased, the mean zone of inhibition (ZOI) was found to increase. Herbal mouth rinse showed antimicrobial activity which is as effective as antibiotics against Lactobacillus and has a superior effect on S.mutans. Findings from the study suggest that herbal mouthwash prepared using ethanolic extract of Ficus benghalensis and stevia have a potential cytotoxic and antimicrobial effect and can be used as an alternative to commercially available products.