Asthma
Asthma was an illness which affected respiration.
Chlorodyne was promoted as a remedy for asthma. (TV: Deep Breath)
The atmosphere on Earth gave Vislor Turlough asthma, hindering his ability to take part in PE at Brendon Public School. (PROSE: The King of Terror)
Petronella Osgood suffered from asthma and had to use an inhaler when scared or excited, a trait not shared by her first or second Zygon doubles. (TV: The Day of the Doctor, Death in Heaven, AUDIO: Narcissus) In 2020 she found herself in need of a new inhaler prescription but was having trouble getting one as doctors were "all busy at the moment." (WC: The Zygon Isolation)