A powder inhaler comprising: a body that is provided with a dispenser orifice; a plurality of reservoirs each containing a dose of powder; a perforator to perforate a predosed reservoir on each actuation; and a dispersion channel including an inlet that is connected to the perforator and that receives the dose of powder from the reservoir, and an outlet connected to the dispenser orifice, the perforator controlled by inhalation, the dispersion channel including two bent channel portions, a first bent channel portion that is connected to said inlet via a first substantially-rectilinear channel portion, and a second bent channel portion connected to the outlet via a second substantially-rectilinear channel portion, the two bent channel portions being interconnected via a third substantially-rectilinear channel portion, the cross-section of the third substantially-rectilinear channel portion being smaller than the cross-section of the first substantially-rectilinear channel portion.