Presently, in the developed countries, oncological diseases have become the most significant factor of the medical treatment costs of the populations, as well as the main reason of premature deaths. This is why there is a huge interest in anti-carcinogenic prophylaxis; this interest has become particularly substantial upon the evidence provided by epidemiological studies that plant derived foods contained numerous phyto-chemicals capable of preventing the development of neoplasms. Cruciferous vegetables can be particularly valuable, since, in their case, an essential, negative correlation between the level of their consumption and the level of incidence of breast, colorectal and lung neoplasms was found. In Central Europe, white cabbage (Brassica oleracea var. capitata) is the most important vegetable of the cruciferous plant family; it is a traditional element of the diets in the countries in this region. Owing to its high consumption level and its availability all year round, this vegetable can be a potentially significant element in the chemoprevention against cancer diseases. At the Chemical Faculty at the Gdańsk University of Technology, multifaceted research projects were initiated and accomplished, with the purpose of assessing the anti-carcinogenic properties of both the fresh and the culinary processed cabbage. In the research projects, various experimental models, diverse doses and forms of the vegetable preparations were applied; they all were as close to the real consumption as possible. The common opinion is that reactive oxygen species (ROS) are one of the triggers of carcinogenic processes; they react with important cellular bio-molecules, change their structure and function, and, thereby, contribute to the transformation of a healthy cell into a neoplasmic one. ROS are also believed to be a cause of many other civilization diseases, as well as of the aging processes. Therefore, one of the project lines carried out by the authors of this paper and dealing with the anti-carcinogenic properties of cabbage, was the assessment of potentiality of phyto-complex of this vegetable to prevent the effects by ROS. The research project was designed so as to make it possible to assess the cabbage at different levels. To start with, its antioxidant activity was measured in vitro and antioxidant substances were determined; next, the capability of cabbage was assessed to: protect other food components against the oxidation; protect cells against the attack by ROS; and, finally, induce endogeneous mechanisms within cells that neutralize the resulting effects by oxidative stress. The paper is a summary of the investigations carried out by three research groups. It was found that the components of both the fresh and the culinary processed cabbage did not only prevent other food components against unfavourable thermo oxidative processes, but they also developed a number of activities allowing the human organism to neutralize reactive oxygen species, and, also, to overcome damaging effects resulting from the ROS activity.