Our objective was to clarify the current understanding of the definition and safety of oral health products among patients and health professionals, and patients’ perception about their communication with physicians and pharmacists regarding those products. Self-administered questionnaires were completed by patients at 17 community pharmacies in 14 prefectures of Japan. For health professionals, we sent a questionnaire to pharmacists and physicians who were registered as members of the Internet-based Medical Doctor's and Pharmacist's Information-Sharing System. The respondents were 242 patients, 158 physicians and 407 pharmacists. Some patients did not categorize dietary supplements as health products, while they did so categorize conventional foods (e.g., fermented soybeans, yogurt). Their understanding of the definition of health products was different from that of health professionals. Less than half of the patients considered that health products might potentiate or attenuate the effects of concomitant drugs, and this view was especially common among the elderly. The percentage of patients who reported that they rarely or never asked for advice from a pharmacist about their use of health products was significantly higher among those who had an incorrect understanding about health products. In conclusion, some patients’ recognition of oral health products was different from that of health professionals, and most patients do not discuss their use of such products unless they are asked. Therefore, it is important for health professionals to check a patient's use of health products and be sure what he or she means when using the term ‘health product’.