Basophils are a type of blood cells (See: Blood). They are a type of the white blood cells and are a type of granulocytes. They play a key role in the functioning of the immune system. They are responsible for many inflammatory reactions of the body and are important in many acute allergic reactions of the body leading to anaphylaxis (See: Anaphylaxis). Basophils are produced in the bone marrow and are then circulated throughout the body with the bloodstream. As part of the immune system, they are instrumental in terminating foreign organisms like bacteria, fungus, and other parasites. Basophils have an important function of consuming other cells including parasitic cells and so are called phagocytes. They contain histamine and heparin. Histamine produced by the basophils are responsible for many symptoms of ordinary allergic reactions including common cold, flu, and others. They manifest in the form of runny nose, itching of the skin, watery eyes, and other symptoms. This is the reason why antihistamines are prescribed in case of common allergic reactions. Basophils also contain heparin that prevents clotting of the blood. They produce serotonin and histamine which induces inflammation. Basophils contain vasodilator histamine that aids in dilating the blood vessels and improving blood circulation. When it comes to their role in the immune system, the cell surfaces contain protein receptors that binds to the immunoglobulin. In people with diabetes, a condition called Basophilia exists where the number of basophils are abnormally high. Also, the complex role of histamine in glucose and lipid metabolism is known to influence blood glucose control.