Diethyl ether is a highly volatile solvent. Like gasoline, it is a liquid which easily evaporates into a gaseous form and which is also highly flammable/explosive. It was used in the 19th and early 20th centuries as an anaesthetic though this is no longer true in the U.S.

Though recreational use is quite uncommon, diethyl ether has been used recreationally both orally (liquid) and inhaled (gas). Oral use has historically been in combination with alcohol, to reduce ether's burn in the mouth (see hoffmann's drops). Inhaled it is most commonly used by pouring it onto a rag and inhaling the fumes through the rag.