While patient held guidelines for the management of chronic diseases have been employed in some countries. There is little evidence of their effectiveness in improving patient outcomes. We hypothesised that a patient held guideline on the management of hypertension combined with a specific exhortation to patients to challenge their medical care where the guidelines did not appear to have been applied would improve blood pressure control, lower average blood pressure, lower average cholesterol, increase the appropriate use of statins and aspirin, and have no impact on patient anxiety. Patients were randomised to the guideline or to standard hypertension information. Measures of anxiety were taken at baseline 2 weeks and one year, blood pressure and cholesterol was measured at one year and case notes examined to determine appropriate statin and aspirin usage.