A delivery device for and method of delivering a powdered substance, in particular a triptan, such as sumatriptan, to the posterior region of a nasal cavity of a subject, in particular for the treatment of headaches, for example, cluster headaches and migraine, and neuropathic pain, the delivery device comprising: a nosepiece for insertion into a nasal cavity of a subject through which the powdered substance is delivered to the posterior region of the nasal cavity of the subject, in particular the upper posterior two thirds of the nasal cavity； and a substance supply unit which is operable to deliver the powdered substance through the nosepiece.
