Novel 4-(2'-pyridylamino)phenylacetic acid derivatives of the formula: ##STR1## wherein R.sub.1 is hydrogen, a halogen, a lower alkyl having 1 to 3 carbon atoms, or nitro, R.sub.2 is hydrogen, a halogen, or a lower alkyl having 1 to 3 carbon atoms, R.sub.3 is hydrogen, a halogen, or a lower alkyl having 1 to 3 carbon atoms, R.sub.4 is hydrogen or a lower alkyl having 1 to 3 carbon atoms, R.sub.5 is hydrogen or --CH.sub.2 CH.sub.2 OR.sub.6 wherein R.sub.6 is a lower alkyl having 2 or 3 carbon atoms and being substituted with 1 or 2 hydroxy groups, provided that R.sub.1 or R.sub.2 is not 4-halogen, or pharmaceutically acceptable salts thereof, and a process for the preparation thereof, pharmaceutical composition of said compounds, and a method of using said compounds as anti-inflammatory and analgesic agents. They have excellent anti-inflammatory and analgesic activities with an extremely weak ulcerogenicity in the gastrointestinal tract. Some of the compounds have superior inhibitory activity against chronic inflammation mediated by cellular immunity.