AIM: Many weapons are available in the arsenal of a dental professional to combat dental caries, which is almost ubiquitously present. From a public health perspective, most of these weapons are far from being an ideal drug. Hence, there is a demand for better and effective antibacterial agents. This factor stimulated the process of the present study. The aim of the study was to determine the effect of ethanol extract of Terminalia chebula on Streptococcus mutans. MATERIALS AND METHODS: Dried ripe fruits of Terminalia chebula were procured and powdered. Physical tests were done to estimate purity of the fruit powder. Hydroethanolic and aqueous extracts were prepared according to standard procedures. Minimum inhibitory concentration of the extracts was determined by tube dilution method and confirmed by agar dilution method. The effect of the hydroethanolic extract on sucrose induced adhesion, glucan-induced aggregation and on glycolysis of Streptococcus mutans was also assessed. Preservative, gelling agent and sweetener were added in suitable quantities to the ethanol extract, and mouthrinse was formulated. Minimum inhibitory concentration of the formulation was also determined. RESULTS: Yield was better in case of aqueous extract. The Minimum inhibitory concentration of hydroethanolic extract was determined to be 2.5%. Minimum inhibitory concentration of the aqueous extract was determined to be 10%. Hydroethanolic extract of Terminalia chebula (2.5%) inhibited sucrose induced adherence and aggregation of Streptococcus mutans in vitro. CONCLUSION: The mouthrinse formulated from ethanol extract of Terminalia chebula demonstrated substantial antibacterial activity and could be used as an effective anticaries agent. CLINICAL SIGNIFICANCE: Terminalia chebula mouthrinse can be effectively used in clinical practice as an anticaries mouthrinse with additional benefit being that it is safe and economical.