This section is from the book "A Guide To The Poisonous Plants And Weed Seeds Of Canada And The Northern United States", by Robert Boyd Thomson, H. B. Sifton. Also available from Amazon: A guide to the poisonous plants and weed seeds of Canada and the northern United States.
Other Common Names: Friar's Cap, Wolfsbane, Iron Hat.
Rydberg lists three members of this genus from Western Canada. One of these, Aconitum columbianum Nutt.
is found in the lower parts of the mountains and sometimes poisons stock, though it is so thinly scattered that losses are comparatively rare. Its chief effect is on the heart and blood vessels, but there are also characteristic secondary effects. The pulse becomes very weak. Bloating is common and nausea and retching are present in all cases. There is apparently a considerable feeling of constriction in the throat, giving rise to repeated attempts at swallowing. The pupils are dilated. Horses sweat profusely and become so weak as to be unable to stand. Death is usually caused by asphyxia. The poisonous character of other species is a matter of history. The European form, Aconitum Napellus L., is the source of the drug aconite, and an Indian species Aconitum ferox Wall., is used by natives of the Himalayas as an arrow poison.
Concerning the treatment for aconite poisoning in persons, Chesnut, in 1898, wrote as follows: "No specific antidote is recognized, but physicians have used atropin or digitalis and nitrate of amyl with good effects. The ordinary emetics and stimulants must be given. Artificial respiration should be continued for a couple of hours if necessary, and a recumbent position must be maintained through the treatment."
Tannic acid is recommended by Gail and Hahner as a chemical antidote. All agree that the use of heart and respiratory stimulants is an important part of the treatment.
Fig. 10. - Monkshood - Aconitum napellus.
The plant arises from a perennial rootstock. It has alternate, palmately lobed leaves which resemble those of certain of its near relatives, the Larkspurs, with which it is often confused, especially in the younger stages. The flowers, too, are arranged as in Larkspurs. They are large and one of the irregular coloured sepals forms the "hood." The five small petals are all alike. The stamens are numerous and the three to five carpels are partly united to form a horned seed capsule as in the Larkspurs. Though similar in many respects, Monkshood and Larkspur may be easily distinguished when in flower by the presence of the hood in one case and the spur in the other.