A 2-pyridylacetic acid derivative having the formula (I): ##STR1## wherein R.sup.1 represents an alkyl having 1 to 15 carbon atoms, an alkenyl having 5 to 20 carbon atoms or an aralkyl having 7 to 15 carbon atoms; R.sup.2 represents hydrogen, a linear or cyclic alkyl, a hydroxyalkyl group, an alkenyl, an aryl, an aralkyl or a group--(CH.sub.2)--A, where n represents an integer of 0 to 3 and A represents a nitrogen-containing heterocyclic group which may be substituted with an alkyl having 1 to 10 carbon atoms or an aralkyl having 7 to 10 carbon atoms and a pharmacologically acceptable acid addition salt thereof. This compound has both effects of the inhibition of gastric acid and the protection of gastric mucosa, which is low in toxicity. Accordingly, it is useful as a therapeutical agent for peptic ulcer disease.