This research investigates the consideration of human health effects within the plan-making process in the East of England. It is based primarily upon questionnaires and interviews with those involved in plan-making. The results indicate that, prior to the implementation of the Strategic Environmental Assessment (SEA) Directive, which established a statutory requirement for the consideration of significant effects on human health in European Union member states, very limited consideration has been given to human health in land use plans. The capacity of the planning system to affect human health is clearly understood by those responsible for their production, but they lack the expertise to consider the health implications of their plans. The SEA Directive, along with reforms to the planning system, does provide a framework for improving the consideration of health, but the capacity of the planning system to consider health must be improved as should dialogue with health practitioners, and the evidence base for health outcomes. Also, analytical and methodological complexity may hinder the ability of planners to consider health, indicating that greater application of the precautionary principle is required to deal with the present uncertainty over human health impacts resulting from the implementation of land use plans.