Dental caries is currently one of the diseases with the highest prevalence and focus of research in public health, one of themain organisms involved is Streptococcus mutans. In this regard, Cuminum cyminum(cumin) has active compounds with antimicrobial properties that suggest its potential for the treatment of dental caries in a less toxic way than current commercial products, which can produce side effects. The objective of this study was to evaluate the in vitro antibacterial effect of C. cyminumethanolic extract at concentrations of 5%, 10%, and 20% with their dilutions at 25%, 50%, and 75% each, on a strain of S. mutans. Susceptibility testing was performed using the KirbyBauer disc diffusion method, and the Minimum Inhibitory Concentration was determined by colony-forming unit (CFU) counting. The results showed that the 20% concentration of ethanolic extract diluted at 50% and 75% was very sensitive, while the pure extract was extremely sensitive against S. mutans. The minimum inhibitory concentration to inhibit the entire S. mutansATCC 25175 strain was the 20% concentration diluted at 25%. The 5% and 10% concentrations did not completely inhibit the S. mutansATCC 25175 strain at any of their dilutions. In conclusion, cumin extracts showed an in vitro antibacterial effect on S. mutans ATCC 25175, with the 20% concentration extract being the most effective and its 25% dilution being the minimum inhibitory concentration of all the evaluated dilutions.