The anti-inflammatory activity of a 1% ketoprofen gel containing 20% Pluronic F-127 was evaluated using the carrageenan-induced rat paw edema method. The activity of the gel was compared with that of other topical nonsteroidal anti-inflammatory drug (NSAID) preparations. The Pluronic gel formulation was significantly more effective against edema formation than other ketoprofen gels used. The 1% ketoprofen gel in the Pluronic base inhibited 53% of the carrageenan-induced edema formation as compared with 38% inhibition obtained with a 3% ketoprofen gel in a Carbopol-based formulation. The topical ED50 of the 1% ketoprofen gel was 2.2 mg/kg whereas the oral ED50 of ketoprofen in a suspension was 6.1 mg/kg, indicating that the relative equiponderal availability of the topical gel was nearly three times that of the oral suspension. The application of 50 mg of the 1% ketoprofen gel on the rat hind paw at various time intervals from 0 to 24 h prior to the carrageenan injection significantly inhibited edema formation in all groups of dosed rats. A significant correlation was found between the percent inhibition of rat paw edema and the log dose of ketoprofen injected subplantarly for the dose range between 0.1 and 10 micrograms/paw.