It reacts with water to form chloral hydrate, a once widely used sedative and hypnotic substance.

[1] Chloral was first prepared, and named, by the German chemist Justus von Liebig in 1832.

Aside from its tendency to hydrate, chloral is notable as a building block in the synthesis of DDT.

For this purpose, chloral is treated with chlorobenzene in the presence of a catalytic amount of sulfuric acid: This reaction was described by Othmar Zeidler in 1874.

Chloral hydrate was routinely administered to patients on the gram scale with no lasting effects.