Wheat sprout extracts have demonstrated antimutagenic activity in vitro. The mechanism of the antimutagenic effect is unclear. Wheat sprouts and wheat grass are rich in chlorophyll, and the antimutagenic activity of wheat sprouts may be accounted for by the presence of this substance, which is known to have antimutagenic and anticarcinogenic activities (see Chlorophyll/Chlorophyllin). Other substances, including flavonoids, may also play a role in these possible activities. Barley grass extracts have been found to protect human fibroblasts against carcinogenic agents. Again, chlorophyll may, in part, account for this effect. Barley grass contains several substances other than chlorophyll that have antioxidant activity and that may contribute to its possible antimutagenic and anticarcinogenic activities.