Objectives To explore consumers’ beliefs and preferences for benefit information in medicine leaflets and examine their understanding and reaction to treatment benefits. Methods Forty-five participants were recruited to eight focus groups, run concurrently in Australia (23 participants in four groups) and the UK (22 participants in four groups). Participants were provided with amended leaflets based on the medicine clopidogrel, containing textual and numerical benefit information presented using numbers needed to treat (NNT).A topic guide which explored use of leaflets, preferences and opinions was used to direct discussion. Focus group discussions were recorded, transcribed verbatim and content analysed using adapted cross-case study analysis. Key findings The consensus was that the inclusion of benefit information was a positive factor. Many participants felt that textual benefit information offered an incentive to take a medicine, although some Australian participants had concerns that included benefit information could create anxiety.The presentation of numerical benefit information provoked strong feelings of disbelief and shock. Participants were surprised that so few people would benefit. Some participants struggled to understand and interpret the NNT and others found it difficult to comprehend the magnitude of the benefit information, instead operating on initial and often crude assumptions of what the data meant. In both countries the provision of numerical benefit information appeared to shake participants’ faith in drug treatments.Participants were concerned about how this might affect the ‘less-informed’ patient. However, in the UK, participants stated that their adherence to treatment was also reinforced by their doctor’s advice. Conclusions Participants wanted to receive information about the benefits of their medicines.However, theymay misinterpret the numerical information provided.