The present study is an attempt to review the toxicity of heavy metals such as Cd, Hg, and Pb and its serious health effects on both man and animals. Chronic cadmium intoxication may give rise to renal tubular dysfunction, anemia, and skeletal damage. Exposure to Cd, Pb, and as can cause mutagenesis, carcinogenesis, teratogenesis, immunosuppression. Therefore, it is important to monitor heavy metal levels in animal tissues which are very important for assessing the potential health risks of metals to humans.