A powder inhalation device comprising a housing containing a pharmacologically active compound, a conduit (8) with an outlet extending into the housing through which a user can inhale to create an airflow through the conduit, a dosing unit (6, 7) for delivering a dose of the compound to the conduit and baffles (9) arranged within the said conduit to aid disintegration of powder agglomerates entrained in said airflow. The baffles (9) comprise a plurality of staggered plates extending into the conduit from opposite sides of the conduit at an angle of less than 90 DEG to the sides of the conduit and are inclined towards the outlet to create a plurality of constrictions within the conduit and a plurality of changes in the direction of the said airflow through the conduit.