ABSTRACT
Some questions of definition arise when considering the roles of herbs and other natural substances in cancer. First, natural products may be sources for specific chemical compounds, which may be extracted and used in purified form. Other natural substances may be consumed as a tea, the rough equivalent of an aqueous extract. Others are consumed whole, as foods, in the normal diet. Some whole foods are wild species, but most modern food varieties have been cultivated, selected and bred over centuries for qualities of taste and appearance. Cultivated varieties may or may not be considered ‘natural’. For purposes here, all plant foods and herbs are considered, but only those of considerable interest are described in detail.
