Chloral hydrate (trichloroacetaldehyde monohydrate) is a hypnotic agent that has been used in physiological experimental in laboratory animals (particularly rodents). 

Chloral hydrate is generally considered to be a good hypnotic, but a poor analgesic—even at anesthetic doses. For initiation/maintenance of surgical anesthesia (and for a smoother induction/recovery period), it generally must be administered with some other anesthetic or tranquilizing agent. It is widely used in physiological experiments because, at hypnotic doses, the drug has minimal effects on cardiorespiratory function. 

When given in small doses, the drug suppresses only the cerebral cortex. Larger doses may cause dangerous respiratory and thermoregulatory depression, cardiac arrhythmias, and severe hypotension. 

Chloral hydrate is metabolized via oxidation by chloral hydrate dehydrogenase to trichloroacetic acid. Trichloroethanol is the active hypnotic metabolite of chloral hydrate and is eliminated as trichloroethanol flucuronic acid. Intraperitoneal administration of chloral hydrate can be very irritating to the peritoneum of rodents. Its use is sometimes associated with post-procedural adynamic ileus accompanied by focal chronic serositis, serosal fibrosis, and/or chronic steatitis of the visceral peritoneum fat deposits. 

There is a lack of controlled studies relative to the anesthetic quality of chloral hydrate which is related to the question of the drug’s ability (when used alone) to produce satisfactory anesthesia/analgesia.