The inhalation device comprises a base unit (100), a mouthpiece (200) and an aerosol head (300). The base unit comprises an air inlet (101), an air outlet (102), a groove (103) for receiving the mouthpiece, and key lock members (104). The mouthpiece comprises a first segment (200a) comprising an air inlet (201) and a lateral opening (202) for receiving an aerosol generator, the first segment being insertable into the groove of the base unit, and a second segment (200b) comprising an aerosol outlet (203). The aerosol head comprises an aerosol generator (301), a liquid reservoir (302), and key lock members (303) complementary to the key lock members of the base unit. The base unit, mouthpiece and aerosol head are connectible with one another such that when engaging the members of the key lock with the complementary members, the aerosol generator is inserted into the lateral opening of the mouthpiece.
