This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
Dilute acetic acid in moderate doses has a cooling eupeptic action. It diminishes thirst partly by causing a flow of alkaline saliva. In large quantity it lessens secretion of acid gastric juice, and so stops digestion and impairs nutrition.
The stronger acid, taken into the stomach, acts as an irritant poison, and has occasionally caused death; it induces burning sensations in the throat and stomach, and acute abdominal pain with tympanitic distension, tightness across the chest, and much anguish; the buccal mucous membrane is whitened, the tongue becomes dry, cold, and tremulous, nausea, and vomiting occur, with hurried, labored breathing, and quick, small pulse; the pupils are dilated; cold clammy perspirations cover the body; nervous tremor and sometimes convulsions have occurred.
This is very similar to that of sulphuric acid.
Heine (Virchow's Archiv, xli., 1867, p. 24) examined the effects of acetic acid brought into direct contact with the blood by injection, and came to the conclusion that the acid decomposes the haemoglobin, expels oxygen from the corpuscles, coagulates their albuminous substance, together with the haematin, causes the passage of this latter into the serum, giving rise to the lac-color of the blood. The red corpuscles become finely dotted in the centre, owing to the coagulation of the albumen. The blood remains fluid after only small doses, but is always coagulated by very large ones. After direct injection of the acid into the blood the temperature falls 2° C., though later on, when the destroyed corpuscles seem to act like a poisonous ferment, rigors and muscular tremor occur, with embolism, and septicaemia and consequent rise in temperature. The above-described discoloration of the blood (lac-color) never takes place after the internal administration of the acid, as it does when injected into the veins.
Citric, tartaric, and other vegetable acids.
As an antidote in poisoning by caus tic alkalies and lime, vinegar is to be recommended, since it is generally near at hand, and the compounds formed by it are not injurious. It is useful also in alcoholic intoxication. Alkalies and their carbonates are chemically incompatible with acetic acid.
The glacial acid is sometimes employed as a vesicant, and is used in the acetum cantharidis as a solvent for the active principle of the Spanish fly, and to increase its efficacy.