Asphyxiation

Asphyxiation, or asphyxia, (PROSE: Revolution Man) was, according to the Brigadier, "lack of oxygen". It could lead to death, as he thought had happened when he once examined one of his UNIT charges. However, as the Third Doctor knew, asphyxiation was not always fatal, and could be recovered from — as the Brig's man certainly did — if oxygen were restored in time. (PROSE: Galactic Gangster)

Asphyxiation could cause one's face to turn blue. (PROSE: Revolution Man) According to tests conducted by Sontaran Field Agent Styre, drowning a human produced asphyxiation in less than three minutes. (TV: The Sontaran Experiment) Strangulation would cause asphyxiation if the victim survived the broken neck. (PROSE: The Sands of Time) The result of crucifixion was usually a slow, painful death by asphyxiation and hypovolemic shock. (PROSE: Byzantium!)

Acid in contact with stone created an asphyxiant miasma, a gas that induced asphyxia. (TV: The Almost People)

Tom Carlton died of asphyxiation and coronary thrombosis when he was attacked by a huge swarm of wasps. (PROSE: Eater of Wasps) Fairies killed many of its victims by making them choke on rose petals flowing out of their mouths, causing asphyxiation. (TV: Small Worlds)

In the 1970s, the Master's Nestene-controlled objects asphyxiated multiple victims "all over the home counties", including George McDermott and John Farrel. (TV: Terror of the Autons)

Asphyxiation was the Ninth Doctor's second guess as to what killed the Empty Child victims. In reality, nothing had — they weren't dead. (TV: The Empty Child)