Olive fruits (Olea europaea L) have several health and nutritional benefits due to their high contents of antioxidant compounds. This study evaluated the hepato-renal toxic effects of pickled olive fruits that were treated with acid black nigrosine dye (ABND) in mice. Twenty male Swiss albino mice (CD-1 ) were used to determine the median lethal dose (LD50) of ABND. Then other forty male mice were equally divided into 4 groups (N = 10) as follows: Group 1 (Gp1) was served as a control group. Gp2 was administered orally with a normal olive fruits extract (NOFE) as 150 mg/kg b.wt. Gp3 was administered with pickled olive fruits extract treated with KOH and ABND (POFE/B/KOH/ABND) as 150 mg/kg b.wt. The last group (Gp4) was administered with ABND alone as 60 mg/kg b.wt. The treatment of all the experimental groups was daily for 2 consecutive months. At the end of the experiment, percentages of body weight (% b.wt.) changes were calculated. Blood and sera samples were collected for determination the hematological and biochemical parameters Liver and kidney tissues were collected for histopathological investigations. The results showed that the group of mice that were treated with POFE/B/KOH/ABND showed significant hepato-renal dysfunctions as evidenced by altering the some of hematological, biochemical and histopathological parameters.