Hemp is a renewable source of cellulose fibre and seed oils. This chapter examines the potential of hemp in ecological architecture and the 'carbohydrate economy'. Combining economic development with ecological sustainability is one of the most crucial problems facing the world's governments. The task of testing, evaluating, publicising and popularising the extraordinary characteristics of hemp products for the construction industry has only just begun. Hemp can play a central role in the transition from a hydrocarbon-based economy to an ecologically sustainable carbohydrate-based economy. A carbohydrate economy promises environmental, economic and social benefits. Carbohydrates from plants could be used to make chemicals, with only a tiny fraction of the pollution generated by the manufacture and use of petrochemicals. Given the economic and environmental impact of the construction industry, it is crucial that materials minimise pollution and waste, and maximise the use of renewable sources of energy and materials.