Introduction. One of the properties of sodium hypochlorite (NaOCl) is dissolution of pulp tissue remaining after instrumentation. Irrigant activation systems aim to improve this property. The objective of this work is to determine tissue dissolution capacity of NaOCl with and without sonic or ultrasonic activation in different concentrations. Methodology. 300 pork palate connective tissue samples of 4.5 * 2 mm obtained 1 day before the study, frozen at-15 ° C in 100% humidity, weighed on an analytical balance and subjected to the action of NaOCl 1%, 3% and 5% with and without activation for 45 minutes, changing the solution every 10 minutes. They were dried on filter paper and weighed again. The data were analyzed by Kolmogorov-Smirnov tests; Kruskal-Wallis and Mann-Whitney. Results and Discussion. NaOCl 1% has a lower dissolution capacity that improves slightly when activated. NaOCl 3% has better dissolution capacity than NaOCl 1%, but the activation does not significantly improve it. NaOCl 5% has greater dissolution capacity, which increases with activation, without significance between sonic and ultrasonic activation, which is due to the fact that the porcine palatine mucosa requires more time for its complete dissolution, since the volume of tissue used is greater than a dental pulp Conclusions. Under the conditions of this study, only NaOCl 5% showed greater dissolution capacity with activation. NaOCl 1% and 3% did not improve significantly with activation.