Interactions between herbal and conventional medicines can occur by either pharmacodynamic or pharmacokinetic mechanisms, resulting in a reduction or increase in the effects of the conventional medicine. Healthcare professionals (HCPs) should always take a full medicines history, including herbal medicines use as well as other complementary products (e.g., food supplements and other dietary supplements), and be aware that they may sometimes affect the efficacy or safety of other medicines the patient receives. A range of resources are available to inform HCPs and patients/carers about potential drug/herb interactions. HCPs and the public need to be aware of the importance of reporting suspected adverse drug reactions (including suspected interactions) to the appropriate regulatory agency. Finally, further research is necessary to ascertain the clinical impact and mechanisms of such interactions, and how adverse outcomes can be avoided.