A dispenser for dispensing a dose of a gaseous, gas borne or droplet substance from a substance source, the dispenser comprising: a body for receiving a substance source, the body having a mouthpiece; a junction member slideably arranged in the body for movement in a longitudinal axis of the body to release a dose of a substance from a substance source, the junction member comprising a socket for receiving a spout of a substance source; a dispenser driver for moving the junction member in the longitudinal axis of the body to release a dose of a substance from a substance source, the dispenser driver comprising a pivot shaft and a cam (23, 231, 232) arranged on the shaft, the dispenser driver being arranged within the body such that rotation of the pivot shaft causes the cam to rotate and apply a force to the junction member so as to move the junction member in the longitudinal axis; a cam follower slideably arranged within the body, the cam follower comprising a base and a substantially rigid protrusion (18a, 18b) extending from the base, the protrusion being arranged between the dispenser driver and the junction member such that a force applied by the cam of the dispenser driver to the protrusion causes the cam follower to slideably move in the longitudinal axis of the body and apply a force to the junction member so as to release a dose of a substance from a substance source; a dispenser cap comprising a hollow body having a lower open end engageable with the body, and an upper open end for receiving a cap closure device for closing the upper open end, the upper open end comprising an engageable portion; and a cap closure device, comprising: an upper cap closure portion for engaging with the upper open end of the dispenser cap to close the upper open end of the dispenser cap; a lower cap closure portion for engaging with the engageable portion to secure the cap closure device to the dispenser cap; and a bistable portion (130, 131, 132, 133) connecting the upper cap closure portion and the lower cap closure portion, the bistable portion being switchable between a first stable form in which the bistable portion is extended, and a second stable form in which the bistable portion is collapsed, wherein, when the bistable portion is in the second stable form, the upper cap closure portion engages with the upper open end of the dispenser cap to close the dispenser cap. a body for receiving a substance source, the body having a mouthpiece; a junction member slideably arranged in the body for movement in a longitudinal axis of the body to release a dose of a substance from a substance source, the junction member comprising a socket for receiving a spout of a substance source; a dispenser driver for moving the junction member in the longitudinal axis of the body to release a dose of a substance from a substance source, the dispenser driver comprising a pivot shaft and a cam (23, 231, 232) arranged on the shaft, the dispenser driver being arranged within the body such that rotation of the pivot shaft causes the cam to rotate and apply a force to the junction member so as to move the junction member in the longitudinal axis; a cam follower slideably arranged within the body, the cam follower comprising a base and a substantially rigid protrusion (18a, 18b) extending from the base, the protrusion being arranged between the dispenser driver and the junction member such that a force applied by the cam of the dispenser driver to the protrusion causes the cam follower to slideably move in the longitudinal axis of the body and apply a force to the junction member so as to release a dose of a substance from a substance source; a dispenser cap comprising a hollow body having a lower open end engageable with the body, and an upper open end for receiving a cap closure device for closing the upper open end, the upper open end comprising an engageable portion; and a cap closure device, comprising: an upper cap closure portion for engaging with the upper open end of the dispenser cap to close the upper open end of the dispenser cap; a lower cap closure portion for engaging with the engageable portion to secure the cap closure device to the dispenser cap; and a bistable portion (130, 131, 132, 133) connecting the upper cap closure portion and the lower cap closure portion, the bistable portion being switchable between a first stable form in which the bistable portion is extended, and a second stable form in which the bistable portion is collapsed, an upper cap closure portion for engaging with the upper open end of the dispenser cap to close the upper open end of the dispenser cap; a lower cap closure portion for engaging with the engageable portion to secure the cap closure device to the dispenser cap; and a bistable portion (130, 131, 132, 133) connecting the upper cap closure portion and the lower cap closure portion, the bistable portion being switchable between a first stable form in which the bistable portion is extended, and a second stable form in which the bistable portion is collapsed, wherein, when the bistable portion is in the second stable form, the upper cap closure portion engages with the upper open end of the dispenser cap to close the dispenser cap.