Open AccessThis work focuses primarily on the histological effects of aqueous extract of moringa on mercury induced wistar rats. Twenty four adult wistar rats weighing between 190-270g were allocated into four groups of six animals each. Group A served as the control and received 0.5ml of distilled water, group B received 0.5ml of moringa extract, group C received 0.35ml of mercury while group D received 0.35ml of mercury and 0.5ml of moringa extract. The oral administration lasted for twenty eight days between the hours of 12-3pm. Twenty four hours after the last administration; the animals were sacrificed under chloroform vapour and dissected. Liver tissues were removed, weighed and trimmed down for histological studies. The results showed that following administration of extract of moringa, there are no degenerated cells; the hepatocytes were not distorted even when administered with mercury. Mercury exposed animals showed distortion of the liver cells. The liver weight of animals in group C was significantly higher (0.001) then group A (control) and group B and D.