This section is from the book "Alcohol, Its Production, Properties, Chemistry, And Industrial Applications", by Charles Simmonds. Also available from Amazon: Alcohol: Its Production, Properties, Chemistry, And Industrial Applications.
A small proportion of the imbibed alcohol is excreted unchanged, mainly through the lungs and in the urine. The actual quantity thus lost is variable. Any influence which hastens absorption into the blood, or stimulates the production of urine, or augments the vigour of respiration, will tend to increase the quantity of alcohol eliminated in an unchanged form. The loss, however, never exceeds 10 per cent. of the quantity of alcohol swallowed, and is usually much less - about 2 per cent. on an average. As little as 1 per cent. of a moderate dose may escape where habitual drinkers are concerned.
There is no evidence that alcohol is ever eliminated to any appreciable extent in the perspiration. It has been detected in the milk of women addicted to alcohol, but probably it does not occur in the milk except when large doses are taken, and even then the amount excreted is too small to affect the health of the infant.
In this connection, it may be noted that the available evidence does not support the popular belief that alcoholic beverages promote the secretion of milk, and are therefore beneficial to nursing mothers. Whether in the form of spirits or beer, alcohol does not seem to have any effect whatever on either the quantity or the quality of the milk secreted.1