Acid

Acid was a chemical compound that was caustic in nature.

Natural Occurrences
Acid could be found on many planets, including large bodies of acid. The seas of Marinus (DW: The Keys of Marinus), 16 Alpha Leonis One (NA: Eternity Weeps) and Endpoint were all composed of acid. (EDA: Hope) The planet Vortis also had pools of acid on its surface. (DW: The Web Planet) Skaro had a river of acid, where the Dalek Emperor attempted to kill Zeg. (TV21: Duel of the Daleks)

Offensive Purposes
Some species used acid as a method of killing. This could include regular weaponry or an impromptu defence.


 * The Doctor used a syringe of prussic acid to kill a Zilgan on the Sense Sphere. (DWA: The Monsters from Earth)
 * A special acid that could destroy silicon-based life was developed and used on Kastria in the form of traps. After being returned to Kastria, Eldrad fell victim to one of these traps. (DW: The Hand of Fear)
 * The calcium-based bodies of Raxacoricofallapatorians were vulnerable to acetic acid. On Raxacoricofallapatorius, criminals were executed by being dissolved in a vat of acetic acid while still alive. (DW: Aliens of London, World War Three, Boom Town)
 * The Doctor defeated the Krotons by using sulphuric acid against them. (DW: The Krotons)
 * On Jaconda, Mestor's body was destroyed with a beaker of acid. (DW: The Twin Dilemma)
 * On Earth, coronic acid was used against the Sontarans Stike and Varl. (DW: The Two Doctors)
 * Cassandra O'Brien's surgeons used moisturisers filled with acid to defend her. (DW: The End of the World)

Other Uses

 * The Humans of Varos used acid as a method of body disposal. The Doctor escaped from being dissolved in an acid bath. (DW: Vengeance on Varos)


 * The Mantis leader, in his attempts to learn the nature of the Doctor's TARDIS, had it submerged in a beaker of acid in his ship's lab. The acid had little effect on the TARDIS. (TVC: Size Control)

Other Facts

 * Diplosians were allergic to citric acid. (DW: The Stones of Blood)