Background: Research into bleaching focuses on new products in order to minimize undesirable effects. This study evaluated the bleaching effectiveness of a new enzymatic-activated dentifrice. Materials and methods: A total of 20 volunteers were bleached with a dentifrice containing 5% lactoperoxidase and 3% carbamide peroxide applied three times a day for two minutes over 21 days. Color was recorded before and after the treatment using a spectrophotometer. CIELAB differences were calculated before and after treatment using the paired t test (P 0.05). Results: Lightness was significantly higher after treatment (P 0.001), ΔE was 5.14. The maxillary central incisors showed greater lightness than the laterals and canines, both before and after treatment, and a greater tendency towards green and blue; the same occurred in the mandibular central incisors in comparison to the canines and laterals. Conclusions: The use of brush-applied enzyme-activated carbamide peroxide at low concentrations with short exposure time is effective for whitening teeth. Clinical implications: Enzymatic dental bleaching is able to increase the efficiency of low concentration peroxides, reducing the potential risk of peroxides on oral tissues.