Objective: Chewing gum may act as a masking or a therapeutic agent against the different chemical compounds that are responsible for oral malodor. An open-label exploratory study investigated the effect of mastication and aromatic components of chewing gum on reducing oral volatile sulfur compounds. Method and materials: Twelve dental students (5 males and 7 females) acted as their own controls. Toothbrushing stopped 12 hours before observations. Measurements included organoleptic and volatile sulfur compound scores and the pH of the anterior and posterior zones of the dorsal tongue. Measurements were made at 9 AM and 12 PM on 1 day for 3 successive weeks: week 1, no gum (control); week 2, test gum; week 3, unsweetened gum base. This open-label study was then completed by an observerblind study, aecording to the same schedule; the recorded measurement was the plaque index. Results: The pH, volatile sulfur compounds, and organoleptic scores were similar for all groups. The pH was more basic in the posterior part than in the anterior zone of the dorsal tongue, irrespective of time and presence or absence of chewing gum. In addition, the volatile sulfur compound score rose transiently immediately after the test gum, and the organoleptic score feil in the first hour only after the test gum. The two chewing gum groups seemed to have a greater reduction in plaque index than did the control (no gum) group. Conclusion: Chewing gum may have a valuable mechanical role in cleaning dental suriaces, and the test gum may temporarily control bad breath. After 3 hours, similar volatile sulfur compound scores were observed for subjects who chewed either test or unsweetened gum base and control subjects. Keywords: chewing gum, masking effect, organoleptic measurement, volatile sulfur compounds