Abstract
BACKGROUND: Patient information leaflets (PILs) for medicines are legally required across the European Union to support safe medicine use, informed decision-making, and treatment adherence. However, they are often criticised for complexity, poor readability, and anxiety-inducing descriptions of side effects. Health literacy (HL), the ability to access, understand, appraise, and apply health information, may affect how patients engage with PILs. Italy has a high prevalence of limited HL, yet population-based evidence on its influence remains scarce. This study examined patterns of PIL use, comprehension, and related behaviours in the Italian adult population, accounting for HL differences. METHODS: A cross-sectional survey was conducted between October 2024 and April 2025 among 1,977 adults (mean age 46.5 years; 63% women). Recruitment combined social media dissemination with general practitioner collaboration to reach older and less digitally active individuals. The questionnaire collected sociodemographic data, HL (using the six-item HLS-EU-Q6 and a single-item functional HL screener), and indicators of PIL engagement, including reading frequency, reasons for non-consultation, comprehension of extracts, anxiety, therapy discontinuation, risk interpretation, and perceptions of commercial influence. Data were analysed using descriptive and inferential statistics. RESULTS: 66% of respondents reported always reading PILs for prescription medicines, and 71% did so for over-the-counter products. Overall, 17.2% had inadequate HL, 52.4% problematic, and 30.4% sufficient. Among sociodemographic variables, only education differed by HL level (2.09 vs. 2.02; p = 0.04). Higher HL was associated with more frequent PIL reading, greater confidence in medicine use (mean 2.22 vs. 1.94; p < 0.001), and lower anxiety (2.21 vs. 1.97; p < 0.001). In contrast, respondents with lower HL more often discontinued therapies after reading PILs (37% vs. 28%; p = 0.02) and overestimated vaccine risks compared with analgesics (25% vs. 9%). Perceiving PILs as commercially influenced was also more common among those with limited HL (p < 0.001). CONCLUSIONS: HL significantly shapes how Italian adults use and interpret PILs, influencing engagement, confidence, anxiety, and therapy behaviours. Current formats may inadvertently widen inequalities by overburdening readers with limited HL. Public health efforts should prioritise simplification, plain language, balanced risk communication, and perceptions of neutrality to promote equitable and safe medicine use. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13690-026-01901-7.