A tracheostomy dilator is curved along its length having a tapering patient end region (5) at one end and an oppositely curved handle region (7) at its opposite end. A passage (10) extends rearwardly along the dilator from its patient end (4) and opens on a side of the dilator at an opening (12) in the handle region (7). The passage (10) is blocked rearwardly of the opening (12) by an insert (2) with a forward ramp surface (23), which directs a guidewire (30). In use, one end of the guidewire (30) projects from the patient end (4) of the dilator and its opposite end extends along the outside of the handle region (7).