Dental and oral disease is a high prevalence in Indonesia 88.8% of the population has dental caries and periodontitis, 93% of children under 12 years of age have dental caries, 67.2% have experienced caries and 43.4% have not been treated. Dental plaque is a soft deposit that is firmly attached to the tooth surface, consisting of microorganisms that cause dental caries. Caries prevention and plaque control can be done by using mouth wash; it will be more effective if you rinse your mouth using herbal mouthwash that contains antioxidants and anti-bacterial. Cocoa Bean Extract (Theobroma Cacao L.) contains secondary metabolites, alkaloids, flavonoids, tannins, steroids and has anti-bacterial, anti-inflammatory properties and has a strong inhibitory effect on S. mutans bacteria. The purpose of the study: to determine the phytochemical content of cocoa beans, determine the effectiveness of the Minimum Inhibitory Concentration (MIC) and Minimum Kill Concentration (KBM) of mouthwash of cocoa bean methanol extract, determine the toxicity of mouthwash of cocoa bean methanol extract, determine the decrease in plaque index before and after gargling with methanol extract of cocoa beans (Theobroma Cacao L.), determine the effectiveness of the pH of the oral cavity before and after gargling methanol extract of cocoa beans (Theobroma Cacao L.). The research method is a laboratory experiment with a post-test only control group design. The research was conducted in the laboratory of the USK Faculty of Veterinary Medicine, and the USK FMIPA laboratory in 2022. Dry samples of 1 kg cocoa beans were macerated with 80% methanol for 3x24 hours; the filtrate was evaporated using a rotary evaporator to obtain a thick methanolic extract of cocoa beans. Phytochemical test results of methanol extract of cocoa beans contain compounds, phenolics, tannins, flavonoids, steroids, terpenoids, saponins, alkaloids. Minimum Inhibitory Concentration Test The average number of colonies of S. mutans ....