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 Hellebore, Helleborus niger. Official in Belgium and Mexico. Belongs to the digitalis group, as it contains helleborin and kelleborein, but is too irritant to be used as a cardiac remedy, at least for long.
A drastic, hydrogogue cathartic, and somewhat emetic. Overdoses cause death in convulsions. The fresh root is vesicant. Helleborin is an acrid narcotic and paralyzant. In comparatively small doses helleborus is diuretic. This latter action has given helleborus some reputation in the treatment of dropsy. It is employed in Homeopathic practice in meningitis with exudation, meningeal effusions, anasarca following scarlet fever, etc., using minute doses of the tincture. The active principle, helleborin, is rarely used. Helleborein, however, is used as a heart tonic.
Theoretically a good argument can be made for helleborus, especially in the treatment of cardiac dropsy. Small doses really do have a positive digitalis action, resembling the action of apocynum, q. v. Apocynum is to be preferred to it.
I have used this drug in the past, when it was more in vogue, and even then abandoned its use. Possibly it may serve well in some cases; but I was never able to judge in which ones its use is justifiable. Small doses often disappoint utterly; but when the dose is run up to the point of the effectiveness the irritant action appears. I understand from other physicians that they have had similar experiences.
The fl. may be given in doses from 1-5 to 3 minims. Helleborin should never be given. Helleborein is given in doses of 1-30 to 1-10 grain. Be cautious with this drug in any form.