From three to six drams, but larger ones can be given with safety. Excessive doses produce profound slumber, complete insensibility, and shallow breathing. The pulse, though at first quickened, becomes soft and indistinct, the pupils are contracted, and complete muscular relaxation is also observed. In poisonous doses death results from reduced temperature and paralysis of the heart. The smaller animals can be recovered from excessive doses by stimulants and the application of hot-water bottles, blankets, bandages, and friction to the skin. The same measures, so far as they can be applied to so large an animal as the horse, would be available in case of an overdose.

It is given to horses in the treatment of meningitis and other irritable conditions of the spinal cord and nerve-centres, and by some it is used as an ingredient in colic mixtures. Its effect in cases of spasmodic contraction of the bowels is produced through the medium of the nerves by which they are supplied, but chloral is not considered to be an anodyne in the same sense as opium.