Dental caries is one of the oral health disorders caused by Streptocuccus mutans bacteria, to minimize the presence of these bacteria can be overcome with the use of mouthwash. Mouthwash with basil leaf extract containing eugenol compounds that are able to prevent bacterial entry and have very strong antimicrobial properties. In the mouth of basil extract use glycerin varies as humectant which affects stability, physical properties to obtain a good dosage of mouthwash. Mouthwash basil extract used excipients of glycerine in variation with concentrations of 15%, 20% and 25%. Physical evaluation performed on mouthwash done for 28 days includes organoleptic observation, the result of the evaluation is the absence of discoloration and sediment, the color produced transparent yellowish green. The difference in taste, the higher the glycerin concentration, the more sweet and the lower the pH, but the resulting pH corresponds to the range of pH of the mouthwash stock value of 7.0 to 7.7. Evaluation of stability performed during the 6 cycles of Cycling test, the results obtained from the stability test made by mouthwash preparation of basil extract did not undergo any changes or had good stability. In the antibacterial test using the formula chosen according to the convenience of use of formula 3 with a concentration of 25% glycerin. The selected formula has an antibacterial inhibitory zone of 10.2 mm. Mouthwash basil leaf extract has a moderate category of bacteria linhibition.