3,4-Diarylisoxazol-5-acetic acids of the formula ##STR1## in which Ar.sup.1 and Ar.sup.2 are the same or different and are selected from phenyl and naphthyl, R.sup.1, R.sup.2, R.sup.3, and R.sup.4 are the same or different and are selected from hydrogen, halogen, trifluoromethyl, lower alkyl, and lower alkoxy, and R.sup.5 is selected from hydrogen, lower alkyl, and lower alkoxy. The compounds have anti-inflammatory, analgesic, and anti-pyretic activities and a low order of toxicity, and methods for their preparation and use are also disclosed.