The disintegration of porous tablets, obtained by powder compression, is being studied. Tablets dissolve into a liquid through a two-step process including (i) an imbibition process inside the porous medium and (ii) a dissolution process of the powder aggregates. First, we show that the imbibition process follows the classical laws of capillarity. Then, we evidence and explain the influence of the presence of trapped gas inside the tablet. Finally, we demonstrate the existence of two limit disintegration regimes appearing at low and high porosity values.