Disaminoacidemia was shown to be of much higher degree in involvement of the intestinal hepatobiliary system in patients with ulcer disease, in addition, in elderly and old people the content of free amino acids (AA) in the blood serum is significantly reduced. Present in the least amounts are methionine, proline, threonine, glutamic acid, glucine, tirosine, and in elderly and senile age, in addition to those listed above, histidine. The level of aspartic acid, lysine, arginine is elevated. The blood content of essential AA expressed in percentages is increased to a more considerable extent and of nonessential and sulphur-containing AA is reduced due to the inhibition of synthesis of essential AA, limitations in the processes of AA conversion in the hepatocyte, including the conversion of phenilalanine to tirosine, methionine and glycine to cysteine, glutamic acid to proline, aspartic acid to beta-alanine. The reasons for these limitations are analysed.