This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol2", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
In relation to its effects on the system, when internally administered, and its special tendency to the urinary and genital organs, this medicine has already been treated of, among the stimulant diuretics (vol. II. p. 642). That it is capable of powerfully stimulating the uterus, along with the other pelvic viscera, there can be no doubt; but it is by no means so certain that it has any special relation to the menstrual function-i.should expect nothing further from it than to excite the uterus generally, and thus produce a determination of blood to the organ, which, when there is a deficiency of menstruation from mere torpor or inertness, might produce a return of the function, like any other stimulant. This it is capable of doing, and for this purpose it is considerably employed. it was highly esteemed by the late Professor Dewees as a remedy in leucorrhoea, operating as a stimulant and alterative to the relaxed and debilitated membrane; and it would seem to be peculiarly applicable to cases of amenorrhoea, connected with this condition of the organ. it should never be administered when there is any active congestion, or acute inflammation of the womb, or a febrile state of the system. The tincture is usually preferred as an emmenagogue, being administered in the same doses as for its effects on the urinary organs.
The local application of cantharides, in the form of a blistering plaster to the sacral or pubic region, in amenorrhoea, about the period for the return of the menses, has been recommended, and will sometimes probably prove serviceable.
Of the other stimulating diuretics, the only one used as an emmenagogue is turpentine or its volatile oil. This has some exciting effect upon the pelvic viscera, and may be used under the same circumstances as cantharides, though less efficient. There is no reason to think that it possesses special emmenagogue properties.