1. A specific fluorimetric method for the determination of prodolic acid in serum has been elaborated and has a limit of detection of 2 microgram/ml. 2. Common anti-inflammatory drugs do not interfere with the method. 3. In rats and dogs, prodolic acid is rapidly absorbed and has a short half-life of elimination. 4. The rate of elimination was marked by secondary rises in the blood level profile which were shown to be due enterohepatic recirculation of prodolic acid. 5. Prodolic acid is highly bound to serum protein.