A series of substituted phenylacetic acid compounds and their derivatives, including the pharmacologically acceptable base salts of said acids, have been found to be active as oral hypoglycemic agents. Preferred member compounds include 6-ethoxy-1,2,3,4-tetrahydronaphthalene-1-carboxylic acid, 6-benzyloxy-1,2,3,4-tetrahydronaphthalene-1-carboxylic acid, chroman-4-carboxylic acid, p-chlorophenylacetic acid, o-methylphenylacetic acid, o-methoxyphenylacetic acid, p-methoxyphenylacetic acid and .alpha.,.alpha.-di(4-methoxyphenyl)acetic acid. Synthetic routes leading to those member compounds which are novel per se are described in some detail.