Refinement in animal experimentation: calling time on the use of chloral hydrate for non‐recovery procedures and euthanasia.

The author criticizes the use of chloral hydrate for refinement in animal experimentation and euthanasia. He explains the principles of replacement, reduction and refinement that provide an ethical framework for the use of research animals and improving their welfare. He describes factors behind the continued use of chloride hydrate as a sedative, hypnotic or anaesthetic agent. He discusses reasons for its unethical use for euthanasia and the availability of more refined choices.