Dietary supplement use in the United States is common. Patients can procure supplements without a prescription, and often do not disclose supplement use to their healthcare providers. Providers and patients may be uncertain about what would be appropriate or helpful in discussions of supplements during routine office visits.To explore provider and patient expectations for discussions of dietary supplements.Semi-structured interviews were conducted with a purposeful sample of healthcare providers from three specialties and their patients who reported taking supplements.Thirty-five outpatient providers (14 primary care, six integrative medicine, and 15 complementary and alternative medicine (CAM) providers) and 107 of their patients.Qualitative analysis of transcripts using grounded theory and iterative review.Both providers and patients raised twelve common topics about dietary supplements that they felt were important to discuss during office visits, such as: supplements taken; supplement risks (interactions, safety/harm, side effects/adverse events); treatment benefits; efficacy; alternative treatments; and patient expectations/preferences for treatment. Some topics were mentioned more frequently by providers than patients, such as how to take, reason for taking, and evidence for use. Providers raised several topics that were mentioned infrequently by patients. Supplement costs and regulations were not brought up by any patients, even though consideration of these topics could influence patient decisions to take supplements. Complementary healthcare providers brought up topics not mentioned by primary care providers, such as the importance of supplement brands and supplement mega-dosing.Patients and providers have concordant views about the need to discuss patient supplement use and ensure patient safety. Patients may undervalue, be unaware of, or discount information about cost or regulations that could affect their decision-making about supplement use. Future studies could examine the value, acceptability, and influence of a more comprehensive approach to discussions to help patients appropriately evaluate supplements.