This section is from the book "Botanic Drugs Their Materia Medica, Pharmacology and Therapeutics", by Thomas S. Blair. Also available from Amazon: Botanic Drugs, Their Materia Medica, Pharmacology and Therapeutics.
Black Cohosh, Macrotys, Cimicifuga racemosa. Official in the Netherlands and the United States. The drug is much reduced in activity by drying.
Hoyt classes it as a mild sedative, the increase of dosage producing frontal headache. Hatcher classes it among the bitters. Bartho-low regarded it as effective when used in dosage sufficient to produce some of its cerebral effects, upon which he laid the emphasis. Johnson regarded it as having a "digitalis action." Wilcox claimed that its "digitalis action" is unimportant and noted only in small doses, but that in large doses it depresses the heart and vaso-motor system, diminished reflex activity, and depresses respiration. Many authorities regard it as a sedative and heart depressant, and some regard it as emmena-gogue. The Homeopathic authorities claim that its toxic symptoms are marked by general relaxation, prostration, weak heart action, and pronounced cerebral disturbance. Potter largely agreed with this and thought it has a feeble ergot-like action.
As a matter of fact, the physiologic action has not been accurately determined. A reason for this consists in the fact that the green and dried drug acts quite differently, an undetermined volatile constituent having a fleeting action not at all regular. In my experience, preparations of the dried drug are notoriously unreliable.
What I have to say is based wholly upon preparations of the recent green drug.
Large doses (10 minims or more fl.) produce a general relaxation and depression, with headache and sometimes diaphoresis. In my hospital service I met many cases of chorea and hysteria and employed the drug therein in full dosage. There was improvement in some cases; but the general results were so irregular and erratic that I wholly abandoned the use of the drug in large doses. The headache it produces is most disagreeable and it often persists. Certainly in the bromides and gelsemium we have relaxing agents more dependable and less dangerous; for large doses of an active preparation of cimicifuga are dangerous. In my judgment, the influence exerted upon the nervous system by large doses of cimicifuga is too irregular to be of any reliable clinical value.
Moderate doses (1 to 5 minims fl.) have a slight effect upon the nervous system, thought to be sedative and antispasmodic. The drug has a reputation in the treatment of chorea. I have thoroughly investigated the matter, having taken a number of typical cases off from all other medication and placing them upon cimicifuga alone. Chorea occurring about the age of puberty was benefited, some cases very markedly; other cases of chorea were only transiently influenced, if at all. My conclusion was that the effect upon the generative organs, more particularly in girls, was such as to relieve choreic seizures dependent upon irregularities of uterine and ovarian function. There are three times as many cases in girls as in boys; and, later in life, it occurs as a complication of pregnancy. So, to my mind, the cases of chorea in young people, not occasioned by endocarditis or rheumatic infection, are benefited by cimicifuga because it influences the generative organs, and not from any effect upon the nervous system as such. Much the same must be said as regards the action of cimicifuga in hysteria - cases due to uterine reflexes are benefited; others are not benefited.
As regards the effect on the heart: cimicifuga does not take the place of digitalis; but I do believe that it rests an irritable heart muscle. The irritable heart muscle of endocarditis, and sometimes of fatty heart, may be steadied and relaxed by this drug. It co-operates nicely with digitalis, much as small doses of opium often do; but it does not take the place of digitalis. There is no doubt at all in my mind that the action of cimicifuga is upon muscular tissue primarily - the muscles in general, the uterus, and the heart.
So, then, it is very apparent why cimicifuga is so valuable in amenorrhea, neuralgic and congestive dysmenorrhea, uterine reflexes, annoying after-pains, and in a host of minor conditions affecting the womb.
Equally apparent is it that myalgic forms of so-called "rheumatism" should yield - or relax - to cimicifuga; but don't neglect eliminative treatment as well.
Cimicifuga certainly does relax muscular tissues. This is a clinical fact, whatever pharmacologic explanation there may be for it. And it is also a fact that the U. S. P. preparations of the drug are more often nearly inert than even fairly active. No wonder the remedy is not appreciated.