To date, no biological control agents have been released against weeds in the family Brassicaceae. One reason is probably the family’s large number of economically important crop species as well as it’s many genera indigenous to North America, which set very high standards for the host range of any potential agent. In addition, the unclear taxonomic relationship of species in the Brassicaceae hamper the establishment of phylogenetically based test plant lists. On the other hand, brassica species have been intensively studied in terms of their secondary compounds and insect-plant interactions, which provides valuable background information for the development of a biological control program. The CABI Bioscience Switzerland Centre is currently working on four invasive brassicas, two of which, Lepidium draba and Isatis tinctoria, will be used to illustrate the above mentioned challenges, the research necessary and prospects (including results of host-specificity tests) for the successful implementation of a biological control program against these weeds.