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.
I have known 1 to 5 min. doses of the tincture arrest the capricious vomiting, also the pyrosis and heartburn of pregnancy, possibly by a stimulant effect on the gastric membrane. Its local application to the cervix, conjoined with its internal administration, often acts with advantage. Dr. Eulenburg recommends 10-min. doses as very serviceable, but I prefer the smaller doses repeated every two or three hours.