The water contents of bioadhesive polymeric films of poly(methylvinyl ether-maleic anhydride) copolymer, stored at two humidities and at two temperatures, have been determined by continuous gravimetry. The water contents of the films increased under storage conditions of increasing humidity. The bioadhesion of these films was assessed using an in vitro bioadhesive tester previously validated in our laboratory. Water uptake during the bioadhesive test was taken into account and the final water content of films recorded as a "corrected equilibrium water content" (CEWC). A good quality second-order polynomial relationship between bioadhesion and the CEWC of films stored at both 23 and 35 degrees C was developed using standard curve fitting analyses. A 2 X 2 factorial design experiment revealed that there was a synergistic relationship between temperature and percentage relative humidity with regard to their effect on the bioadhesion of polymeric films, presumably due to their combined effect on film water content. These findings have implications for both the storage and packaging of hydrophilic polymeric films.