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.
When vinegar is taken continuously for five to six weeks, it causes emaciation, and in cases of obesity was formerly used with the object of taking down superfluous fat. A wineglassful was given each morning, fasting, and again at bedtime, but serious consequences, such as phthisis, etc., having occasionally followed this treatment, it has fallen into disuse.
There are on record some remarkable cases in which the use of potash salts, and especially of liquor potassae, has reduced the amount of fat deposited, but these remedies are by no means always effective for this purpose, nor should they be employed without real necessity and due care, for fear of inducing a spanaemic condition. In a case of local excessive deposit of fat round the neck of a girl, which was very unsightly, and for which no available treatment could be at first suggested, the use of 15 to 20 min. doses of liquor potassae ter die, led to marked improvement, and so quickly as to be clearly traceable to the remedy (Lancet, i., 1873). In some other cases of fatty tumor, liquor potassae has also been given with success as regards diminution of the growth.