The invention relates to sulfonyl-containing 3,4-diaryl-3-pyrrolin-2-ones compounds having formula (I) ##STR00001## wherein R.sub.1 is selected from the group consisting of 4-methylsulfonyl, 4-aminosulfonyl, hydrogen, 2-, 3-, or 4-halogen, C.sub.1 C.sub.6-alkyl, cyclopentyl, cyclohexyl, C.sub.1 C.sub.4-alkoxy, hydroxy, cyano, nitro, amino or trifluoromethyl; R.sub.2 is selected from the group consisting of 4-methylsulfonyl, 4-aminosulfonyl, hydrogen, 2-, 3-, or 4-halogen, C1 C6-alkyl, cyclopentyl, cyclohexyl, C.sub.1 C.sub.4-alkoxy, hydroxy, cyano, nitro, amino or trifluoromethyl; and R.sub.3 is selected from the group consisting of hydrogen, methyl, ethyl, n-propyl, i-propyl, c-propyl, n-butyl, isobutyl; provided that when R.sub.1 is a methylsulfonyl or aminosulfonyl group, R.sub.2 is any group as defined above except a methylsulfonyl or aminosulfonyl group; and when R.sub.2 is a methylsulfonyl or aminosulfonyl group, R.sub.1 is any group as defined above except a methylsulfonyl or aminosulfonyl group, also to processes for the preparation of such compounds, to pharmaceutical compositions containing such compounds, and to the medical use of such compounds in the treatment of diseases relating to the inhibition of cyclooxygenase-2 (COX-2).