The drug release and swelling characteristics of cataplasms may be evaluated using artificial sweat. In our study, these characteristics were compared among brand name and generic cataplasms containing nonsteroidal anti-inflammatory drugs (NSAIDs ; indomethacin (IM) (8 products), ketoprofen (KP) (7 products) and flurbiprofen (FP) (4 products)) using artificial sweat and the apparatus described in JP 14 Dissolution Test Method 2. For cataplasms containing IM and FP, the degree of swelling of generic products was less than that of brand name products but there was no significant difference in release rate. On the other hand, for KP-containing cataplasms, disintegration of the base material was observed for three of the four generic products tested, and all four had higher release rates than the brand name products. Thus, the drug release testing method used in the present study showed that the release and swelling characteristics differed between brand name and generic cataplasms and we felt that it was a useful way of evaluating their quality.