Background: Melatonin is a free radical scavenger. It has also antioxidant effects through its stimulatory actions on antioxidant system. Objective: We conducted this study to examine the effect of different oral doses of melatonin on liver tissue. Methods: We used 42 rats—6 rats in each group. Group I served as the control group; group II rats were pretreated with only melatonin; group III w...