Citrus is well-known for its nutrition and health-promotion values. This reputation is derived from the
studies on the biological functions of phytochemicals in Citrus fruits and their derived products in the
past decades. In recent years, the antioxidant activity of Citrus fruits and their roles in the prevention
and treatment of various human chronic and degenerative diseases have attracted more and more attention.
Citrus fruits are suggested to be a good source of dietary antioxidants. To have a better understanding
of the mechanism underlying the antioxidant activity of Citrus fruits, we reviewed a study on the
antioxidant activity of the phytochemicals in Citrus fruits, introduced methods for antioxidant activity
evaluation, discussed the factors which influence the antioxidant activity of Citrus fruits, and summarized
the underlying mechanism of action. Some suggestions for future study were also presented.