Barley (Hordeum vulgare) is an important and ancient cereal crop, which has largely evolved from food grain to a feed and malting grain. The nutritional composition can be increased in barley grain by introducing a specific gene into the breeding grain that can be adapted explicitly for food use. With this breeding process, the barley cultivars can be developed as colored kernels, due to many phytochemical constituents such as anthocyanins, carotenoids, flavonoids, phenolic acids, and other phytochemical compounds that are synthesized in barley through secondary metabolism. These phenolic compounds are also considered potent antioxidants, free radical scavengers, metal chelators, and inhibitors of lipid peroxidation. Potential health benefits, such as the ability to act as antioxidants, immune enhancers, and inhibitors of premalignant lesions, have been demonstrated for carotenoids and phenolics. Additionally, the grain color of barley can vary from light yellow to purple, blue, black, and violet, which is mainly caused by the level of anthocyanins in the pericarp and aleurone layer. The presence of β-glucan in whole barley grain has been largely credited for good human health and nutritional applications. β-Glucan reduces hypertension and diabetes by regulating blood cholesterol and glucose levels, reducing the risk of ischemic heart disease, coronary heart disease, and colon cancer.