The root vegetables are a large and important group in the vegetable category. Tubers, rhizomes, true roots, and bulbs are commercialized as nutritional foods for human daily life. Growing underground, the root vegetables absorb a great amount of nutrients from the soil and store high concentrations of biologically active chemicals such as antioxidants, polyphenolics, fibers, vitamins, iron, and several types of carbohydrates. Root vegetables not only contribute their nutritional values to human living but also exert functional characteristics for human health promotion through dietary intake. Chapter 3 emphasizes seven common and favorable root vegetables in day-to-day life and discusses their remarkable potentials for anticancer, anticarcinogenesis, antioxidant, and immunoregulation as well as other functions regarding health improvement and detoxification. Evidence from both investigations in monotherapy and combination are summarized for their functional ingredients such as micromolecules such as carotenoids, polyacetylenes, organosulfur compounds, glycoalkaloids, phenylpropanoids, anthocyanins, polyphenolics, and sesquiterpenoids, and macromolecules such as polysaccharides, glycoproteins, and lectins. In addition, the best cooking process for high preservation of bioactive ingredients in several root vegetables is also mentioned. One wild root vegetable and three herbal roots are also introduced, which may be used to prepare special diets for primary health need.