Background The graphical content of the Medicines Package Inserts (MPIs), such as illustrations and typographic features should be legible and appropriate, as required by international pharmaceutical regulations. Objectives To study: (1) the frequency and type of MPIs' key graphic elements, (2) their compliance with regulations and (3) how educated people understand them. Methods Descriptive study: characterisation of the graphical content of 651 MPIs. Usability study: illustrations and tables (purposively selected) were evaluated with questionnaires in three groups of humanities undergraduates (illustrations only, illustrations plus text and text only). Results Descriptive study: illustrations and tables were respectively identified in 6.3% and 11.8% of the MPIs. The illustrations were mainly related to how to take/use the medicine. Non‐recommended graphical representations were found (e.g. italic or underline). Usability test: legibility issues were identified, especially for the group of isolated illustrations. Discussion & conclusions The scarce use of illustrations and tables possibly affected the legibility of the MPIs. Compulsory legibility tests are needed to guarantee the MPIs' proper use, thus contributing to a safe use of medicines. Overall, this study highlighted the need to carefully revise/assess the MPIs' design and probably increase health information experts' awareness on this issue.