Ether and chloroform both have relatively narrow therapeutic windows - the toxic dose is very close to the minimum active dose. But they were one of the few true anaesthetics at the time (late 1800s). Alcohol was also used for surgery but it's slower and inhibits clotting. In fact often it'd be a combination of all three, known as ACE [1]. This worked okay-ish, as the GABA-ergic synergy was able to suppress consciousness and memory without poisoning the patient's heart or liver (as) severely.

The other big issue was flammability.

Ether still takes enough time to reduce consciousness that you have a good minute or two (minimum) of struggle. It's not "towel over face, muffled screaming, then sleepytime". But an attacker with advantage of surprise and a decent grapple could usually get the target dosed before they could break free.

[1] https://en.m.wikipedia.org/wiki/ACE_mixture