The aqueous extract from Terminalia chebula was tested for its ability to inhibit the growth and some physiological functions of Streptococcus mutans. The extract strongly inhibited the growth, sucrose induced adherence and glucan induced aggregation of S. mutans. Mouthrinsing with a 10% solution of the extract inhibited the salivary bacterial count and salivary glycolysis. Mouthrinsing with the extract significantly reduced total bacterial counts and the total streptococcal counts in the saliva samples obtained up to and including 3 h after rinsing, compared with the counts obtained prerinsing or after placebo rinsing. The extract successfully inhibited glycolysis of salivary bacteria for up to 90 min postrinsing.