Paraldehyde is a colorless liquid solidifying below 50° F., and soluble in ten parts of water. It has a strong ethereal odor and unpleasant taste. It is a pure hypnotic, like chloral, having about half its power and many of its qualities without the dangers of chloral.

In its action the cerebrum is first affected, and sleep induced with no primary stage of excitement. The medulla is next affected, and next the spinal cord. It has little or no control over pain. In medicinal doses it is not paralyzing to the heart, and does not, as a rule, leave headache or unpleasant after-effects.

It is irritant to mucous membrane, and is likely in time to impair digestion. It gives an unpleasant odor to the breath, and if used for a long time it may produce nasal ulcers, cerebral congestion, and vasomotor paralysis. It sometimes causes erythema or reddening of the skin. Average dose, e xxx.-2 mils, in water, either plain or with simple syrup. It must be well diluted.