This is a short review of the genus Brassica and their ability to provide anticancer effects when included in the diet. Broccoli consumption has increased steadily, following the finding that including broccoli in your diet can slow or prevent a number of cancers. Many other Brassica vegetables share this property, due to the presence of a relatively unique group of chemicals, the glucosinolates. Glucosinolates have no known bioactivity themselves, but are hydrolysed to release isothiocyanates, highly reactive compounds that can activate the mammalian cellular transcription factor Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and by so doing, improve host defence. At one time a single mechanism of cancer prevention was considered to be responsible: increasing detoxification enzymes to clear chemical carcinogens and thus stop the initiation of cancer. Today additional mechanisms, many of them triggered by activation of the transcription factor Nrf2, have been uncovered; these expand our understanding of prevention further than cancers caused by chemicals and extend the range of prevention to include slowing of progression as well as initiation. Furthermore, accumulating data support the idea that chronic inflammation, which aggravates many chronic diseases including cancer, may be controlled by dietary brassicas, via Nrf2. There is a role for plant scientists in optimizing content of glucosinolates and the myrosinase-dependent action to form bioactive isothiocyanates from the glucosinolates.