Volatile sulfur compounds (VSCs) produced by bacteria in niches of the oral cavity play a major role in the etiology of bad breath, and can be easily detected by a portable sulfide monitor (Halimeter). To investigate the effect of an oral hygiene program on VSC levels, Halimeter readings were taken from 55 healthy dental students during a course in oral hygiene training, including instruction on brushing, flossing and professional tooth cleaning. Ten students who received no oral hygiene training served as a negative control. The oral hygiene status was measured using the papillary bleeding index (PBI). PBI and VSC values did not show significant changes during the study period of 10 weeks in the control group. In the test group, PBI values significantly decreased compared to baseline and the control, indicating that the oral hygiene program had a benefit on the oral hygiene status. The VSC values also decreased significantly during the study period compared to baseline and the control. It was concluded that in a group of dental students, a thorough oral hygiene training program was capable of reducing the oral level of VSC Halimeter readings.