Tormentil. Potentilla tormentilla, Potentilla canadensis.

Tormentil. Rhizoma Tormentillae, P. G. Tormentille, Fr. Tormentillwurzel, G. Tormentilla, It. Tormentila, Sp.—Various species of the rosaceous genus Potentilla have been employed in medicine. (See A. J. P., 1875, 109.) It is asserted that our common P. canadensis L. is a valuable sudorific and diuretic.

Potentilla Tormentilla Neck. (Tormentilla erecta L., T. officinalis Curt.)—The tormentil, or septfoil, which was formerly in the Secondary List of the U. S. Pharmacopoeia, is a small perennial plant of Europe and Asia. All parts of the plant are astringent, especially the rhizome, which is the part employed. The rhizome of tormentil is cylindrical, somewhat fusiform, branching and more or less curved, from 2.5 to 8 cm. long, and from 0.5 to 1.5 cm. thick, brown or blackish externally, and reddish within. It has a slight aromatic odor and a very astringent taste. It contains a red coloring principle, soluble in alcohol, but insoluble in water, and considerable quantities of a peculiar tannin (tormentil-tannic acid, C₂₆H₂₂O₁₁). Rembold found that tormentilla red has the same composition as rhatany red, and yields the same products of decomposition when fused with potassium hydroxide. He also obtained kinovic acid, C₂₄H₃₈O₄, and small quantities of ellagic acid, C₁₄H₆O₈. (A. J. P., 1868, 311; from Ann. Chem., cxliv, 5.) The root is said to be used for tanning leather in the Orkneys and Western Islands of Scotland, and for staining leather red by the Laplanders. Tormentil is a simple and powerful astringent, applicable to all cases of disease in which this class of medicines is indicated. It may be given in substance, decoction, or extract. The dose of the powder is from thirty grains to a drachm (2.0-3.9 Gm.).

The Dispensatory of the United States of America, 1918, was edited by Joseph P. Remington, Horatio C. Wood and others.