An introducer for a tracheostomy tube is formed of several articulated sections (24) that can be changed from a relatively flexible state to a more rigid state by tightening a tension member extending along the introducer using an actuator at its machine end. In its flexible state the introducer can be inserted into and removed from the tube. The introducer is put in its more rigid state for use in inserting the tube into a tracheostomy. Alternatively or additionally the introducer could have several gripping rings on its outside towards its patient end and two elongate members that can be slid relative to one another to enlarge the patient end so that the gripping rings engage and grip the inside of the tube, thereby enabling the introducer to pull the tube through the tracheostomy from its patient end.