Our fully automated formalin paw assay for rodents is validated for use in screening potential compound formulations for their analgesic effects. Formalin injection induces a biphasic response of characteristic flinching and licking movements. Rats or mice are fitted with a metal band on the rear paw receiving an injection of formalin. The animal is then placed into a detection chamber where the associated software electromagnetically detects and subsequently measures specific flinching movements. The biphasic analysis is divided between 0 and 9 minutes and 10 and 60 minutes following injection. Morphine is used as the positive control. Upon comparison with manual observation, the automated system is not statistically different and has a much higher accuracy rate.