A toothbrush having a body and a treatment device is disclosed. In one aspect, the toothbrush comprises: a body comprising a handle portion, a head portion and a longitudinal axis; a plurality of tooth cleaning elements extending from the head portion; a treatment device coupled to the body so as to be alterable between a storage state and a use state, the treatment device comprising: a housing; a power source disposed within the housing; and an electromagnetic radiation source disposed within the housing and operably coupled to the power source.