The practice of embalming via chemical fluids has been used for centuries. The main objectives of this form of preservation are to keep the body from decomposing, help the tissues retain their color and softness, prevent both biological and environmental hazards, and preserve the anatomical structures in their natural forms. This is accomplished with a variety of chemical substances that can be separated generally into groups by their purposes. Disinfectants are used to kill any potential microbes. Preservatives are used to halt the action of decomposing organisms, deprive these organisms of nutrition, and alter chemical structures in the body to prevent decomposition. Various modifying agents are used to maintain the moisture, pH, and osmotic properties of the tissues along with anticoagulants to keep blood from clotting within the cardiovascular system. Other chemicals may also be used to keep the tissue from carrying displeasing odors or particularly unnatural colors.