Editing Inhalation (section)

== Other substances – deliberate ==

=== Recreational use ===
[[Nitrous oxide]] ("laughing gas") has been [[Recreational use of nitrous oxide| used recreationally since 1899]] for its ability to induce [[euphoria]], [[hallucinogenic]] states and [[Relaxation (psychology)|relaxation]], and is legal in some countries.

[[Helium]] can be inhaled to give the voice a reedy, duck-like quality, but this can be dangerous as the gas is an [[asphyxiant gas|asphyxiant]] and displaces the oxygen needed for normal respiration.<ref name="Grass">{{Cite journal| title = Suicidal asphyxiation with helium: Report of three cases Suizid mit Helium Gas: Bericht über drei Fälle| journal = Wiener Klinische Wochenschrift| volume = 119|issue =9–10|date = 2007|doi = 10.1007/s00508-007-0785-4|author = Grassberger, Martin|author2 = Krauskopf, Astrid |pages = 323–325 |language=de, en| pmid = 17571238|s2cid = 22894287}}</ref> 

Various illegal gaseous, vapourised  or aerosolized [[recreational drugs]] exist, and are classed as [[inhalant]]s.

=== Medical use ===

==== Diagnostic ====

Various specialized investigations use the inhalation of known substances for diagnostic purposes. Examples include [[pulmonary function testing]] (e.g. [[nitrogen washout]] test, [[Diffusing capacity|diffusion capacity]] testing ([[carbon monoxide]], [[helium]], [[methane]])) and [[diagnostic radiology]] (e.g. [[Isotopes of xenon|radioactive xenon isotopes]]).

==== Therapeutic ====

Gases and other drugs used in anaesthesia include oxygen, nitrous oxide, helium, xenon, [[Inhalational anaesthetic|volatile anaesthetic agents]]. Medication for [[asthma]], croup, cystic fibrosis and some other conditions.