Substituted 1-phenyl-4-phenylcarbamoyl-2-pyrazolin-5-ones, e.g. those of the formula ##STR1## wherein each of R, R' and R" is alkyl, alkoxy, halo or trifluoromethyl, or at most 2 thereof are hydrogen; or their salts with therapeutically acceptable bases, are anti-inflammatory and anti-arthritic agents.