Abstract: Cobalt,an essential trace element, is widely used in industrial production. Cobalt plays an important physiological role in human body. However, excessive intake of cobalt can cause a variety of toxic effects on human body. This article reviews the physiological function and impact on human health of cobalt and its compounds, including the general toxicity, mutagenicity, carcinogenicity, reproductive and developmental toxicity, in order to raise the awareness on those exposure to cobalt, and to provide orientation for further research on effects of cobalt on human health.