This section is from the book "A Practitioner's Handbook Of Materia Medica And Therapeutics", by Thos. S. Blair. Also available from Amazon: A Practitioner's handbook of Materia Medica and Therapeutics.
Iris Versicolor, Blue Flag. In large doses a reliable preparation of iris containing the unchanged oleoresin is purgative, cholagogue, and diuretic, but large doses are irritant and should not be long used except in intractable diseases of the liver. Give 10 to 15 I. doses of ec. tr., as the fluidextract is seldom active. The trouble with this drug is that its oleoresin is gradually replaced with red tannates during growth. This is particularly the case with all southern-grown iris. The eclectics value this drug very highly and take the utmost care in its manipulation, whereas it has been dropped from the U. S. P., since the official preparations failed to give results.
In small doses it is a highly useful remedy, being markedly alterative and directly stimulant to the entire glandular system, but more particularly influencing the pancreas and the intestinal glands. It promotes retrograde tissue metamorphosis. It is indicated in deficient elimination from the skin and kidneys accompanied by jaundice and clay-colored stools, in irritable conditions of the gastro-enteric mucous membranes occasioned by altered or morbid secretion and by inaction of glandular tissues. The oleoresin in I or 2 gr. doses is valuable in chronic and malarial jaundice, but in most of the indications for small doses of iris a fluid preparation is preferable. Iris is peculiarly effective in sick headache and cholera morbus, nausea, pyrosis, and gastralgia. One or 2 I. doses of ec. tr. every hour suffice in these indications, and some cases do well upon even smaller doses. As an alterative, in 3 to 5 I. doses, it is effective in many glandular enlargements and in pustular and chronic skin diseases. The dose may be run up to 10 I., especially in the treatment of syphilis marked by glandular inactivity, but do not begin with such large doses. There is no reason why a reliable fluidextract of this drug cannot be made, and doubtless some makes are reliable. The U. S. P. revisers made a distinct mistake in dropping it from the eighth revision. The homeopaths claim that dilutions of this drug are effective in a host of subjective phenomena that proper analysis resolves into physiologic indications similar to those stated above. Their lower triturations of Irisin are effective, and are used by them in gonorrheal rheumatism as well as in digestive disturbances.