FIELD: organic chemistry, medicine, gastroenterology. SUBSTANCE: invention relates to group of derivatives of aminoethylphenoxyacetic acid of the following formula: 
where R1 means hydrogen atom, lower alkyl group or aralkyl group; R2 means hydrogen atom or halogen atom being carbon atom with label (R) means carbon atom in (R)-configuration; carbon atom with label (S) means carbon atom in (S)- configuration, or their pharmaceutically acceptable salts and pharmaceutical compositions stimulating effect of β2- and β3-adrenoceptors and containing derivatives of aminoethylphenoxyacetic acid as active component, agents used for pain relief and method of pain relief. EFFECT: valuable medicinal properties of compounds. 9 cl, 1 tbl
