Regeneration is a Time Lord process. When a Time Lord is mortally wounded or dying, their body cells change and rejuvenate themselves, changing the Time Lord's physical form (and personality)

Causes of regenerationEdit

The DoctorEdit

1st to 2nd: Old age (although some people think his energy was drained by Mondas)

2nd to 3rd: Forced regeneration by the Time Lords, as part of his exile sentence

3rd to 4th: Body cell poisoning due to radiation exposure to the Great One's crystal web, process 'pushed' by his old mentor K'anpo Rimpoche

4th to 5th: Injuries caused from falling from the Pharos radio telescope

5th to 6th: Spectrox toxaemia poisoning, having given the cure to his companion Peri

6th to 7th: Injuries caused from the Rani's attack on the TARDIS

7th to 8th: Shot in gang war, open heart surgery performed by doctors who had no idea of his Time Lord physiology

8th to War: Killed in ship crash on the planet Karn, resurrected by the Sisterhood to drink the Elixir of Life to trigger his regeneration

War to 9th: Old age

9th to 10th: Absorbed the energy from the Time Vortex, from Rose to save her

10th to 11th: Body cell poisoning due to absorbing radiation from the Immortality Gate's radiation control booth, to save Wilf

11th to 12th: Old age, granted new regeneration cycle by the Time Lords

The MasterEdit

(Though most of his regenerations are not shown or preferenced, and he stole the body of Tremas in 'The Keeper Of Traken')


1st to 2nd: Decided it was 'time for a change', though it is referenced by the Doctor that she was harmed by the Key to Time's energy