Purpose: To assess the antimicrobial effects of different natural and semi-natural mouthrinses on isolates of S. mutans obtained from the saliva of Saudi children and reference strains of S mutans (ATCC 25175). Study design: Saliva samples were collected from 20 children. Natural and semi-natural mouthrinses included were herbal mix mouthrinse, cranberry mouthrinse, chlorhexidine digluconate mouthrinse, cranberry extract mixed with chlorhexidine digluconate mouthrinse, chlorhexidine digluconate mouthrinse with alcohol (positive control), and distilled water (negative control). The microbiological examination tests were minimal inhibitory concentration, minimal bactericidal concentration, and zone of inhibition for the saliva isolates of S. mutans while zone of inhibition test only for reference strain of S. mutans. Results: For reference strain in a comparison with the distilled water, the herbal mix, cranberry, cranberry mixed with chlorhexidine, chlorhexidine, and chlorhexidine with alcohol showed significantly increased zones of inhibition by 36.38, 36.25, 26.13, 17.75, and 12.38, respectively. For saliva isolates in a comparison with the distilled water, the herbal mix, cranberry, cranberry mixed with chlorhexidine, chlorhexidine, and chlorhexidine with alcohol showed significantly increased zones of inhibition by 38.00, 34.25, 22.94, 16.50, and 16.44, respectively. Chlorhexidine with alcohol showed significantly lower minimum inhibitory and bactericidal concentration than the other groups. Conclusions: Herbal mix and cranberry mouthrinses could be effective natural alternative to chlorhexidine mouthrinse with or without alcohol in affecting tested parameters.