Tromethamine is extensively used in biochemistry and molecular biology. Because tromethamine (in the form of R-NH2) is a proton acceptor with a pK of 7.8, it is an effective buffer that can be used to maintain the pH of body fluids. Tromethamine is indicated for the prevention and correction of metabolic acidosis. When administered intravenously as a 0.3 M solution, tromethamine acts as a proton acceptor and prevents or corrects acidosis by actively binding hydrogen ions (H+). It binds not only cations of fixed or metabolic acids, but also hydrogen ions of carbonic acid, thus increasing bicarbonate anion (HCO3‾). TromeThamine also acts as an osmotic diuretic, increasing urine flow, urinary pH, and excretion of fixed acids, carbon dioxide and electrolytes. A significant fraction of tromethamine (30% at pH 7.40) is not ionized and therefore is capable of reaching equilibrium in total body water. This portion may penetrate cells and may neutralize acidic ions of the intracellular fluid.