A heterocyclic aromatic oxazole compound of the formula (I) ##STR1## wherein Z is an oxygen atom; one of R and R.sub.1 is a group of the formula ##STR2## wherein R.sub.3 is lower alkyl, amino or lower alkylamino, and R.sub.4, R.sub.5, R.sub.6 and R.sub.7 are the same or different and each is hydrogen atom, halogen atom, lower alkyl, lower alkoxy, trifluoromethyl, hydroxy or amino, provided that at least one of R.sub.4, R.sub.5, R.sub.6 and R.sub.7 is not hydrogen atom, and the other is an optionally substituted cycloalkyl, an optionally substituted heterocyclic group or an optionally substituted aryl; and R.sub.2 is a lower alkyl or a halogenated lower alkyl, and a pharmaceutically acceptable salt thereof. The heterocyclic aromatic oxazole compound and pharmaceutically acceptable salts thereof have antipyretic action, analgesic action, anti-inflammatory action, and particularly, selective inhibitory action on cyclooxygenase-2 (COX-2), and are expected to be useful as anti-inflammatory agents with less side-effects such as digestive tract disorders.