BackgroundMetaphors in communication can serve to convey individuals’ backgrounds, contexts, experiences, and worldviews. Metaphors used in a health care setting can help achieve consensual communication in professional–patient relationships. Patients use metaphors to describe symptoms, or how disease affects them. Health professionals draw on shared understanding of such metaphors to better comprehend and meet patient needs, and to communicate information that patients can more easily integrate into their lives.This study incorporated a theoretical framework based on four worldviews, each with an underlying foundational metaphor (root metaphor). The use of these root metaphors (formism, mechanism, contextualism, and organicism) can have an explanatory function and serve to impart new meanings, as each type of metaphor can lead to a particular interpretation. The study aimed to extract and discuss the root metaphors, with a view to analyzing the communication between health professionals and patients.MethodsIn a case study in Spain over a six-month period, we analyzed the content of recorded, transcribed interviews conducted by one nurse with 32 patients who had chronic illnesses. We inductively extracted five categories that emerged from the interviews: blood sugar, cholesterol, exercise, blood pressure, and diet. We then examined these categories from the standpoint of each of the four root metaphors using two approaches: A series (deductive) and an emergent (inductive) approach.ResultsThe results show that the nurse tended to primarily use two worldviews: mechanism and formism. In contrast, patients tended to favor mechanism when discussing cholesterol, blood pressure, and blood sugar levels, whereas contextualism was predominant when the category was diet or exercise.ConclusionsThis study adds to the existing literature on health professionals and patients’ communication. It shows how the use of Pepper’s root metaphors help to analyze the communication between the nurse and patients. Furthermore, it shows they are both using different root metaphors when they are talking about illness and treatments especially regarding blood sugar, cholesterol, exercise, blood pressure, and diet. Further qualitative and quantitative studies are needed to solidly these findings.Electronic supplementary materialThe online version of this article (10.1186/s12909-017-1059-0) contains supplementary material, which is available to authorized users.