Metalloids (especially Ge, As, Sb, and Te) are toxic elements that can geographically be abundant on the earth's crust. Generally, metalloids leach from the geologic materials such as rock, atmospheric dust, minerals, and geologic process such as earthquake and volcano eruptions which input the metalloids to soil and water over the permeable level and, thus, increases the bioaccumulation of them into the plants and aquatic organisms. Consumption of fish and vegetables with contaminants has a negative impact on both human and animal health. Medical geology can perform a significant role in helping to maintain the environment's safety by detecting the amounts, forms, and sources of metalloids. Therefore, the current chapter comprehensively explores the existing knowledge on the (i) role of natural geologic materials and processes on releasing metalloids to the environment, (ii) their potential paths of them to the environment and their bioaccumulation, (iii) human and veterinary health effects of metalloids on medical geology, and (iv) the risk management strategies to reduce the bioavailable fraction of metalloids in the environment.