Abstract: H.sub.2 -receptor antagonist ascorbate compounds, derived from the lactone form of 3-ketohexuronic acid of Formula ##STR1## where (X) may be 1, 2 or 3 and (Y) may be 1 or 2, R.sub.1 and R.sub.2 are both hydrogen or R.sub.1 may be hydroxyl, R.sub.2 hydrogen or the O-alkylidene, 5,6-diacyl, 6-acyl derivatives thereof having two to sixteen carbon atoms, or a 6-phosphate, R.sub.3 being an organic base or a salt thereof having one or more basic functional groups, having H.sub.2 -receptor antagonist properties and capable of reacting with nitrous acid, and a process for the preparation of said compounds.