Background: Patients may have unrealistic expectations of preventive treatment and frequently do not take long-term medication. Involvement of the patient in the decision to start such medication may improve this, but enabling an informed decision is notoriously difficult. Aims: To explore patients' perceptions of preventive medication, the desire for informed choice and how this could best be achieved. Method: Purposive sampling was used to select patients registered with one of two general practices in South England. Audio recording, transcription and computer-assisted textual analysis were conducted for focus group discussions. Results: This was a small study, but the majority of focus group participants who had been prescribed a preventive medication said they received very little or no information about benefits and disadvantages when it was started. Some felt that doctors did not want to share information. Older participants thought that choice was over-rated, trusted their doctor to recommend appropriate medication and did not necessarily wish to be involved in the decision. Younger participants wanted to be more involved. However, even those who expressed little interest in involvement felt that personalised information compared with population norms comparing individuals to the 'average person' would be helpful. Written information specific to the individual and on how the medication or lifestyle changes might affect them was considered welcome. Conclusions: Doctors need to be sensitive to patients' preferences for involvement in the decision-making process and for the way information on risk is shared. Providing written information specific to the individual patient is likely to facilitate shared decisions about preventive medication.