Lappa is the dried root of burdock, Arctium Lappa, Linn. (N.O. Compositae), or of other species of Arctium, collected from plants of the first year's growth. The plants are widely distributed throughout Europe and the United States, and the dried roots are official in the U.S.P. The roots are nearly simple, fusiform, of variable length, and from 5 to 20 millimetres in diameter near the crown. The dried roots are frequently split or in broken pieces, greyish-brown externally, wrinkled longitudinally, with a somewhat annulate crown, which may be surmounted by a woolly tuft of leaf-remains; the fracture is somewhat horny; a dark cambium separates the thick brownish bark from the yellowish porous and radiate wood, and there is a central cavity which may contain a white pith-like tissue. The drug has a slight odour, and a mucilaginous, sweetish, and slightly bitter taste.
Constituents.—The chief constituent of lappa appears to be a bitter crystalline glucoside; other constituents are inulin, fixed and volatile oils, pectin, and sugar.
Action and Uses.—Lappa is said to have a diuretic and diaphoretic action. It has been used in cases of chronic skin disease, and in the gouty, scorbutic, scrofulous, and syphilitic diatheses. It is administered in the form of decoction, fluidextract, or syrup, prepared from the extract; as much as a pint of the decoction may be given daily.
Dose.—1 to 6 grammes (15 to 90 grains).
- Decoctum Lappae, B.P.C.—DECOCTION OF LAPPA. Syn.—Decoction of Burdock. 1 in 20.
- Dose.—30 to 120 mils (1 to 4 fluid ounces), or more.
- Fluidextractum Lappae, U.S.P.—FLUIDEXTRACT OF LAPPA. Syn.—Extractum Lappae Fluidum.
- Lappa, in No. 60 powder, is exhausted with alcohol, 49 per cent., and the strength of the product adjusted so that 1 fluid part represents 1 part of the drug. Average dose.—2 mils (30 minims).