New data indicate that primary dysfunction in the tumour microenvironment, in addition to epithelial dysfunction, can be crucial for carcinogenesis. These recent findings make a compelling case for targeting the microenvironment for cancer chemoprevention. We review new insights into the pathophysiology of the microenvironment and new approaches to control it with chemopreventive agents. The microenvironment of a cancer is an integral part of its anatomy and physiology, and functionally, one cannot totally dissociate this microenvironment from what have traditionally been called 'cancer cells'. Finally, we make suggestions for more effective clinical implementation of this knowledge in preventive strategies.