Unopened metal bottle containing trichloroethylene, made by ICI Ltd., English, 1940-1960

Trichloroethylene is known as Trilene. It is a volatile liquid introduced as an anaesthetic agent in 1934. Trilene was used during labour. It was inhaled via a mouthpiece before each contraction. This provided pain relief rather than full anaesthesia. The use of Trilene in obstetrics has declined since the development of portable inhalers delivering nitrous oxide mixed with oxygen. Nitrous oxide is pleasanter to inhale and has fewer side effects.