The inhibitory effects of the ethyl acetate extract and capsaicin (1) and dihydrocapsaicin (2) isolated from fruits of Capsicum annuum chili pepper type, and synthetic capsaicinoid derivatives (N-(4-hydroxyphenylethyl)decamide (3), (E)-N-(4-hydroxy-3-methoxybenzyl)-3,7-dimethylocta- 2,6-dienamide (4), 4-hydroxy-3-methoxy-N-((E)-3, 7-dimethylocta-2,6-dienyl)benzamide (5) andN-(4-hydroxy- 3-methoxybenzyl)decamide (6) at different concentrations were evaluated against Streptococcus mutans. The minimum inhibitory concentration at which the ethyl acetate extract prevented the growth of S. mutans was 2.5 mg/mL; those of the isolated compounds 1 and 2 were 1.25 μg/mL, while 3 was 5.0 μg/mL, and 4, 5 and 6 were 2.5 μg/mL, respectively.