Cancer, also known as malignant tumors, refers to the abnormal proliferation of cells, and these proliferating cells may invade other parts of the body. In humans, more than one hundred types of cancer are currently known. Many cancers can be prevented by eating more fruits, vegetables, and whole grains. The treatment of cancer, whether it is through chemotherapy, surgery, or radiotherapy, is a huge burden on the body. Once malignant metastasis occurs, it becomes challenging to achieve a complete cure regardless of the method employed. Therefore, the treatment of cancer remains a significant challenge for human beings. In recent decades, dietary phytochemicals have become hot topics in the field of medical research. Many dietary phytochemicals in plant foods have the remarkable ability to inhibit various cancer cells. As a result, scientists from around the world are working to discover the functions of dietary phytochemicals in plant foods to provide evidence for anti-cancer or cancer prevention. The aim of this Special Issue is to provide research and review articles that elucidate the anticancer activity of dietary phytochemicals, with a special emphasis on cancer treatment, cancer prevention, the research and development of dietary phytochemicals as anticancer molecules, their synergistic effects with the clinical chemotherapy drugs for anticancer treatment, and the mechanisms of food phytochemicals in combating cancer. The articles in this Special Issue are expected to be available to people around the world as anti-cancer or anti-cancer applications to promote the health of human beings.