The state of Oklahoma is planning to execute death row inmates with drugs intended for use on animals. Lawmakers want to switch away from the only brand of anaesthetic that has been used in the US for lethal injections because there is not enough to go around. The replacement is likely to attract controversy because it is currently used by vets to anesthetise animals for operations. Other states are watching closely and may well follow suit, but such a move is likely to face a challenge from human rights groups to ensure that it is safe to use.