One initiative, which has not been fully evaluated, is distribution of the guidelines to patients. The large AHCPR guideline programme in the United States included the full guideline, a summary for professionals and a summary for patients (Colling 1994). Evaluation appeared to be limited to the distribution of these guidelines and the impact on practice was not measured (Colling 1994). When the Scottish (SIGN) clinical guideline programme was initiated much of the AHCPR methodology was adopted and acknowledged, but the patient guideline was not included. The purpose of this study is to evaluate the effect of providing patients with a clinical guideline (edited to be understandable to a lay person) on the overall management and control of their hypertension coupled with an explicit exhortation from the medical team to become involved in their own care.