The invention relates to a unit for the micronization of a solid active agent, such as a salt, preferably table salt (NaCI), for inhalation, comprising a micronizer driven by a motor. The unit according to the invention is characterised in that micronization is performed by a unit constituted by a closed rotary drum (2) receiving a solid active agent having the same grain size, preferably 0.1-4 mm, as table salt (NaCI), where the wall surfaces of the micronizer unit are made at least in part of a material having a filtering capacity of 0.1-1000 μm, the material preferably being a mesh-like or microperforated material. A further unit according to the invention is characterised in that the micronizer consists of a rotary block (23) made of the active agent, a friction block (24) adapted to be in frictioning relation with the rotary block, and a clamping mechanism (25) adapted for holding the friction block (24) in position and for clamping the friction block (24) to the rotary block (23), the micronizer being disposed in a closed housing (11), and the wall surfaces of the housing (11) being at least in part made of a material having a filtering capacity of 0.1-1000 μm.
