A wide range of health benefits have been attributed to wheatgrass, the young grass of the common wheat plant Triticum aestivum. Its components include chlorophyll, flavonoids, and vitamins C and E. Forms of wheatgrass include fresh juice, frozen juice, tablets, and powders, with compositions varying according to their production processes, as well as to the growing conditions of the wheatgrass. Laboratory in vitro studies, mostly using the fermented wheat germ extract, have demonstrated anti-cancer potential and have identified apoptosis as a possible mechanism. In animal experiments, wheatgrass demonstrated benefits in cancer prevention and as an adjunct to cancer treatment, as well as benefits to immunological activity and oxidative stress. Clinical trials show that wheatgrass may induce synergistic benefits to chemotherapy and may attenuate chemotherapy-related side effects, as well as benefit rheumatoid arthritis, ulcerative colitis, hematological diseases, diabetes, obesity, and oxidative stress. However, all the trials were small and a number of methodological problems arose. No adverse events of wheatgrass have been reported, although some forms pose problems of tolerability. The popularity of wheatgrass continues to grow. Nevertheless, the advantages seen in the clinical trials need to be proved in larger studies before clinical recommendations for the public can be given.