Tincture: take 2-4 ml of the tincture three times a day.

Citations from the Medline database for the genus Symphytum

ComfreyBehninger C Abel G Roder E Neuberger V Goggelmann W [Studies on the effect of an alkaloid extract of Symphytum officinale on human lymphocyte cultures]

Planta Med 1989 Dec;55(6):518-22 (Published in German)Brauchli J Luthy J Zweifel U Schlatter C Pyrrolizidine alkaloids from Symphytum officinale L. and their percutaneous absorption in rats.

Experientia 1982 Sep 15;38(9):1085-7Culvenor CC Clarke M Edgar JA Frahn JL Jago MV Peterson JE Smith LW Structure and toxicity of the alkaloids of Russian comfrey (symphytum xuplandicum Nyman), a medicinal herb and item of human diet.

Experientia 1980 Apr 15;36(4):377-9Fell KR Peck JM British medicinal species of the genus symphytum.

Planta Med 1968 May;16(2):208-16Franz G [Studies on the mucopolysaccharides of Tussilago farfara L., Symphytum officinalis L., Borago officinalis L. and Viola tricolor L]

Planta Med 1969 Aug;17(3):217-20 (Published in German)Gracza L Koch H Loffler E [Biochemical-pharmacologic studies of medicinal plants. 1. Isolation of rosmarinic acid from Symphytum officinale L. and its anti- inflammatory activity in an in vitro model]

Arch Pharm (Weinheim) 1985 Dec;318(12):1090-5 (Published in German)Hirono I Mori H Haga M Carcinogenic activity of Symphytum officinale.

J Natl Cancer Inst 1978 Sep;61(3):865-9Wagner H Horhammer L Frank U [Lithospermic acid, the antihormonally active principle of Lycopuseuropaeus L. and Symphytum officinale. 3. Ingredients of medicinal plants with hormonal and antihormonal-like effect]

Arzneimittel forschung 1970 May;20(5):705-13 (Published in German)