Regional proteolysis and average daily levels of acidity in different parts of the stomach in long term follow up periods (up to 16 years after the surgery) are analysed. The depressed levels of the secretion remained during all the long term period. In older patients with isolated SPV the level of acidity is decreasing, mainly in distal parts of the stomach by the 11th-16th year after the surgery. There is an intestinal type of digestion in the parts of the stomach that do not contain hydrochloric acid. The intestinal type of digestion is more expressed after the SPV combined with gastrojejunal anastomosis. A high level of acid secretion was demonstrated in 9.7% of cases after the SPV.