Purpose: The aim of the present study was to evaluate the clinical efficacy of an experimental dentifrice (CH) containing an antimicrobial agent (1% chloramine-T). Materials and Methods: A clinical, fully randomised, double-blind comparative study was designed for 30 selected patients aged 15 to 50 years, with no periodontal disease, decay or other oral diseases, good general health and the presence of dental plaque and sulcus bleeding. Baseline Turesky modified plaque index (PI) and sulcus bleeding index (SBI) were scored for all patients. Volunteers randomly received the experimental dentifrice (CH) or a commercial-brand dentifrice containing triclosan (TR). Both dentifrices were provided in identical, number-labelled tubes, and the subjects were instructed to use the supplied dentifrice only for their usual oral hygiene, three times a day for a duration of 7 days. After 7-day use of dentifrices, the PI and SBI were assessed again. The data obtained were subjected to the Kruskal- Wallis test, followed by Dunn's post hoc test. Results: After 7-day use of dentifrices, the PI scores diminished significantly for both evaluated dentifrices. The SBI values decreased significantly for both experimental and commercial-brand dentifrices. Conclusions: Both dentifrices reduced PI and SBI. By comparing the experimental and gold-standard dentifrice, it was found that there was no statistically significant difference between the PI and SBI scores after their use, suggesting that they exerted a similar effect on the oral health indexes. Parole chiave: clinical trial, dentifrices, development of formulations, oral health