Knowledge, Attitudes, and Clinical Practices Regarding Food-Drug, Herb-Drug, and Supplement-Drug Interactions: A Pilot Cross-Sectional Study Among Healthcare Professionals in Portugal.

Background/Objectives: The concomitant use of conventional medicines with foods, food supplements, and herbal products has increased, raising concerns about interactions. Despite this, healthcare professionals' knowledge and clinical practices in this domain remain incompletely characterised. This study aimed to assess knowledge, attitudes, and clinical practices regarding food-drug, herb-drug, and supplement-drug interactions among healthcare professionals (HPs) in Portugal. Methods: A cross-sectional pilot study was conducted among 311 HPs using an online questionnaire; participants were recruited through convenience and snowball sampling. The instrument evaluated perceptions, practices, and knowledge (22 items; score 0-22). Descriptive statistics and non-parametric tests were used for group comparisons. Results: Most participants (90.6%) recognised the clinical relevance of herb-drug interactions; however, only 57.6% reported routinely asking patients about food supplements or herbal product use, and 46.0% about teas or infusions. The median knowledge score was 9.00 (interquartile range 9.00), with a mean of 9.34 ± 5.91. Significant differences were observed between professions (p < 0.001): pharmacists achieved the highest scores and nurses the lowest. In exploratory analyses, academic training and continuing education were associated with higher knowledge, whereas professional experience was not. Conclusions: Among the professionals studied, a discrepancy exists between perceived clinical relevance and actual practice, with important gaps in technical knowledge. Within the limits of this sample, the findings point to a need for improved education and structured clinical approaches to enhance patient safety when medicines and natural products are used concomitantly.