Background: The use of complementary medicines (CMs) is prevalent across the world. Some CMs, such as St John's Wort, when taken with specific pharmaceutical medicines, may cause drug-herb interactions. In this context, pharmacists have the opportunity to play an important role in preventing harm to patients. Objective: The aim of this study was to explore real-life pharmacy practice in relation to CMs in New South Wales, Australia. Methods: The study design involved ‘pseudo-patient’ pharmacy visits while posing as a patient's relative requesting St John's Wort and using a standardized set of questions to document details of the interaction with a range of pharmacy staff. Results: Of the 110 metropolitan pharmacy visits made, the pharmacy workforce who were involved in assisting the pseudo-patient's request included 51 pharmacists (46.4%), 57 pharmacy assistants (51.8%) and 1 naturopath (0.9%). Advice that may have resulted in harm to the patient, was offered by pharmacists in 11.8% (n = 13) of the encounters, and 20.9% (n = 23) by pharmacy assistants. Conversely, advice that prevented harm was provided by only 17.3% (n = 19) pharmacists and 10.9% (n = 12) pharmacy assistants. History-taking was not attempted by 84 pharmacy staff. Conclusion: The majority of pharmacy staff involved in this study did not manage a request for a CM with known drug-herb interactions in a way that would prevent harm. These findings highlight the need for the pharmacy workforce to engage in education and training in CMs, with a focus on how to consult evidence-based resources regarding interactions in the interest of patient safety.