Healing coma

A healing coma was a natural process that allowed Time Lords to heal from particularly serious yet non-fatal damage without the need for regeneration. (TV: Planet of the Daleks, PROSE: Vanishing Point)

The Sixth Doctor entered a healing coma to recover from an aborted regenerative collapse. While asleep, he intended to "edit" his memory of a premature encounter with Jack Harkness, a companion from his personal future. (AUDIO: Piece of Mind)