The purpose of this study was to evaluate in a double-blind placebo-based study the effects of fluoxetine over a period of 16 weeks on the frequency of binging and purging and on fluctuations in the levels of cariogenic organisms and saliva secretion rate of patients (n = 30) with bulima nervosa. Profile analysis suggested that, over the course of the study, binging and purging frequency and Streptococcus sobrinus salivary levels decreased significantly in the fluoxetine group as compared with the placebo group. Our finding that S. sobrinus levels decreased 16 weeks after subjects were on medication suggests that the salivary levels of these organisms could serve as an objectively measured indicator of patient compliance with antibulimic therapy.