Indian Journal of Forensic Medicine & Toxicology, April-June 2021, Vol. 15, No. 2 4203 Toxicity of Cadmium Chloride on White Rats Liver and the Protective Role of Brassica Nigra Seed Extract Nahla Kamal Asaad 1 , Qasim Azeez Razooqi 2 , Mohammed Ahmed Mustafa 3 1 Asst. Prof. College of Dentistry, University of Kirkuk , Kirkuk /Iraq, 2 Asst. Prof. College of Education for Pure Sciences , University of Tikrit, Tikrit/Iraq, 3 Asst. Lec. Department of Pathological Analysis, College of Applied Sciences University of Samarra. Iraq Abstract The study designed for the toxic role of cadmium chloride on the liver of mice from both a physiological and histological aspects. The animals were treated with a dose of 5 mg/kg of body weight for 30 days. And the protective role of Brassica nigra seed extract against cadmium chloride toxicity. This pilot study was conducted on 20 adult white rats divided into 4 equivalent groups including the control group: Animals in this group received a dosed of distilled water for 30 days. The placebo group was treated with cadmium chloride at a dose of 5 mg/kg of body weight for 30 days and returned as an infected control group. While in the third group, animals treated with cadmium chloride were dosed with Brassica nigra seed extract at a dose of 200 mg/kg of body weight for 30 days. The fourth group was dosed with Brassica nigra seed extract at a dose of 200 mg/kg of body weight for 30 days. After 30 days, liver enzymes including aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) were measured by spectrophotometric method. In addition to making tissue sections of the liver. The treatment of rats led to a significant increase (P≤0.05) in liver enzymes compared with the control group. It also led to histopathology in the liver tissue, while the Brassica nigra seed extract acted as a protective role against the toxicity of cadmium chloride. Keyword: cadmium chloride, Brassica nigra, aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP). Introduction The increased emissions of both minerals into the environment and their lack of ability to rapidly biodegrade have increased the risk of human exposure to them. The main methods of exposure to cadmium and lead are ingestion and inhalation due to their presence in food and air, as well as in tobacco smoke [1] . The American Agency for Toxic Substances and Disease Registry (ATSDR) has ranked cadmium seventh and lead second on its priority list of hazardous substances [2] . Cadmium poisoning is a global health problem that leads to infection in many organs, and in some cases it may cause death. Cadmium production, consumption and release into the environment without proper treatment resulted in air, water and soil pollution. And that long-term exposure to cadmium through water, air and diet leads to the problem of different organs of cancer problem for these organs [3] . Cadmium is a heavy metal, which is very toxic and its use in various forms in the chemical industry (dye, paint) as well as the metallurgical industries (alloys) [4] . Numerous studies have demonstrated its toxic nature to the liver by administering cadmium chloride to mice that produce cell necrosis and lipid changes [5] . The chemical is highly toxic the liver generally metabolizes it into a non-toxic chemical, but sometimes the non-toxic or less toxic substance also activates to the highly toxic metabolite. Therefore, the chemical burden increases stress on hepatocytes and leads to hepatic disturbance due to degenerative cells, necrosis, tumors, etc. [6] . Cadmium has the ability to spread through various organs of the body quickly, and most of the cadmium ingested enters the liver and kidneys [7] . The liver is the organ most targeted by cadmium toxicity