The objective of this study was to evaluate the effect of tablet integrity on the dissolution rate. The model drug used for this study was aspirin. A dissolution study was performed with three commercially-available aspirin tablets (ZORprin, Bayer 8-h aspirin and Bayer aspirin), two of which were sustained-release tablets. For ZORprin, the average dissolution data indicated that the in vitro release rate of aspirin was consistent with the intended design of the sustained-release wax matrix tablets only when the tablets were intact. The split tablets showed a consistently higher release profile over time, with a 50% higher release at 6 h. However, the Bayer 8-h aspirin and plain aspirin tablet data showed that tablet integrity had no significant impact on the dissolution rate, because the intact and split tablets showed similar drug release profiles over time. In conclusion, care should be taken to administer sustained-release tablets, avoiding any breaking or crushing of the tablets unless this is directed by the manufacturer.