Prickly Comfrey (Common name)

General poisoning notes:

Prickly comfrey (Symphytum asperum) is a naturalized herb found in parts of southern Canada. The plant contains pyrrolizidine alkaloids, which can cause veno-occlusive symptoms leading to liver cirrhosis. The plant can also accumulate toxic amounts of nitrates. Animals do not normally eat the plant because of the bristly hairs on the leaves. However, swine given the plant as green fodder showed signs of nitrate poisoning. Long-term use of the plant as food could lead to liver dysfunction (Cooper and Huxtable 1984, Huxtable 1989).

References:

  • Cooper, M. R., Johnson, A. W. 1984. Poisonous plants in Britain and their effects on animals and man. Her Majesty's Stationery Office, London, England. 305 pp.
  • Huxtable, R. J. 1989. Human health implications of pyrrolizidine alkaloids and herbs containing them. Pages 41-86 in Cheeke, P. R., ed. Toxicants of plant origin. Vol. I. Alkaloids. CRC Press, Inc., Boca Raton, Fla., USA. 335 pp.

Nomenclature:

Scientific Name:
Symphytum asperum Lepech.
Vernacular name(s):
prickly comfrey
Scientific family name:
Boraginaceae
Vernacular family name:
borage

Go to ITIS*ca for more taxonomic information on: Symphytum asperum

References:

  • Agriculture Quebec. 1975. Noms des maladies des plantes du Canada/ Names of plant diseases in Canada. Quebec City, Que., Canada. 288 pp.
  • Alex, J. F., Cayouette, R., Mulligan, G. A. 1980. Common and botanical names of weeds in Canada/Noms populaire et scientifiques des plantes nuisibles du Canada. Revised. Agric. Can. Publ., Ottawa, Ont., Canada. 132 pp.
  • Bailey, L. H., Bailey, E. Z. 1976. Hortus third. Revised. MacMillan, New York, N.Y., USA. 1290 pp.
  • Scoggan, H. J. 1978, 1979. The flora of Canada. Nat. Mus. Nat. Sci. (Ottawa) Publ. Bot. 7(1)-7(4). 1711 pp.
  • Van Wijk, H. L. 1911. A dictionary of plant names. Martinus Nijhoff, The Hague, The Netherlands. 1444 pp.
  • Victorin, M. 1964. Flore Laurentienne. 2nd ed. Univ. Montreal, Montreal, Que., Canada. 952 pp.

Geographic Information

  • British Columbia
  • Manitoba
  • Nova Scotia
  • Ontario
  • Prince Edward Island
  • Quebec

References:

  • Bailey, L. H., Bailey, E. Z. 1976. Hortus third. Revised. MacMillan, New York, N.Y., USA. 1290 pp.
  • Boivin, B. 1966, 1967. Énumération des plantes du Canada. Provencheria 6. Nat. Can. (Que.) 93: 253-274; 371-437; 583-646; 989-1063. 94: 131-157; 471-528; 625-655.

Image or illustration

Images: prickly comfrey - Google Search

Toxic parts:

  • all parts
  • leaves
  • roots
  • stems

References:

  • Cooper, M. R., Johnson, A. W. 1984. Poisonous plants in Britain and their effects on animals and man. Her Majesty's Stationery Office, London, England. 305 pp.
  • Huxtable, R. J. 1989. Human health implications of pyrrolizidine alkaloids and herbs containing them. Pages 41-86 in Cheeke, P. R., ed. Toxicants of plant origin. Vol. I. Alkaloids. CRC Press, Inc., Boca Raton, Fla., USA. 335 pp.

Notes on Toxic plant chemicals:

This plant contains pyrrolizidine alkaloids such as echimidine. These alkaloids cause veno-occlusive symptoms in animals. Total alkaloid content (as a percentage of dry weight) for fresh leaves is about 0.01% and for dry leaves, about 0.059%. Many members of the genus contain much higher concentrations of alkaloids in the roots (Huxtable 1989).

Toxic plant chemicals:

  • echimidine
  • nitrate

References:

  • Cooper, M. R., Johnson, A. W. 1984. Poisonous plants in Britain and their effects on animals and man. Her Majesty's Stationery Office, London, England. 305 pp.
  • Huxtable, R. J. 1989. Human health implications of pyrrolizidine alkaloids and herbs containing them. Pages 41-86 in Cheeke, P. R., ed. Toxicants of plant origin. Vol. I. Alkaloids. CRC Press, Inc., Boca Raton, Fla., USA. 335 pp.

Animals/Human Poisoning:

Note: When an animal is listed without additional information, the literature (as of 1993) contained no detailed explanation.

Swine

General symptoms of poisoning:

Notes on poisoning:

Prickly comfrey is not normally ingested by animals because of the bristly hairs on the leaves. This plant can accumulate nitrates. In Britain, swine were poisoned when given prickly comfrey as green fodder. Symptoms were typical for nitrate poisoning, including apathy, labored breathing, cyanosis, and methemoglobinemia (Cooper and Johnson 1984).

References:

  • Cooper, M. R., Johnson, A. W. 1984. Poisonous plants in Britain and their effects on animals and man. Her Majesty's Stationery Office, London, England. 305 pp.

Another search?