ASTRINGENT, a term comprising a group of agents that tend to shrink mucous membranes and raw surfaces and to dry up secretions. They are usually classed according to their mode of action into (I) those that decrease the blood supply by narrowing the small blood-vessels (adrenalin and cocaine are in this group) ; (2) those that abstract water from the part as glycerine and al cohol; and (3) those that coagulate the superficial layers and form a crust, as the metallic astringents. They are used in medi cine to reduce swollen mucous membranes in inflammations of the nasal, alimentary and urinary passages. They are frequently employed in attempts to dry up excessive secretions and to stop the oozing of blood.