"Picrorhiza is the dried rhizome of Picrorhiza Kurroa, Royle." 'Br.
Kutki, Katki, Kuru, Kuruwa, Kaur, Karru, Kutaki, Kali-kutki, or Black Kutki, Katukurogani.
Picrorhiza Kurroa Royle (P. Kurrooa Benth.), more properly known as P. Lindleyana (Wall. Wettst.), is a low, hairy perennial herb (Fam. Scrophulariaceae), indigenous to the Alpine Himalayas. The rootstalk or the rhizome has long been used in India and has been frequently spoken of by European and Mahometan writers as black hellebore, but is essentially different.
Properties.—Picrorhiza occurs "in cylindrical pieces two to five centimetres long, and four to eight millimetres thick, sometimes terminating in a stem or scaly leaf-bud; brittle. Cork greyish-brown, wrinkled, with transverse leaf scars and small buds. Fracture short. In transverse section internally dark and porous, with a thin, greyish cork and narrow ring of tangentially elongated wood-bundles. No odor; taste very bitter." Br.
Picrorhiza resembles externally the rhizome of Gentiana Kurroo Royle (Fam. Gentianaceae), the latter, however, is uniformly brown internally, whereas the rhizome of Picrorhiza is darker or black, whence its name kali or black kutki. It is the dried rhizome of an Alpine-Himalayan plant, Kurroa. From this rhizome H. Warden has separated a glucoside, picrorhizin, which is freely soluble in water and alcohol and appears to be the bitter principle of the drug; also a red-brown, resinous, tasteless body, picrorhizetin, and, perhaps, cathartic acid (Pharmacog. Indica, vol. 3).
Uses.—The natives of India attribute active antiperiodic power to picrorhiza, which appears to be a powerful bitter tonic with slight laxative action. It is given in doses of from one to twenty grains (0.065-1.3 Gm.) as a tonic and from forty to fifty grains (2.6-3.2 Gm.) as an antiperiodic, usually in combination with aromatic.
Off. Prep.—Extractum Picrorhizae Liquidum, Br.; Tinctura Picrorhizae, Br.