Hyoscyamus niger (black henbane, hyoscyamus), H. albus (white henbane).
A member of the plant family SOLANACEAE. Annual or biennial upright herbaceous plant
with an angular hairy stem and soft hairy leaves. Dirty yellow purple-veined trumpet-like
flowers; smooth, capsular fruits which open when ripe, common on light or sandy soils.
Animals most affected
Cattle, horses, (pigs).
Ingestion of the fresh plant, (not common as it has an unpleasant odour), or of contaminated
fodder. Poisonings rare.
Contains the anticholinergic alkalcid hyoscyamine, atropine and scopolamine. The
seeds are the most toxic part of the
plant. Drying does not reduce the toxicity. Toxic
doses not known.
Same peripheral and central effects as atropine poisoning:
late onset of mydriasis, which then persists, with possibility of blindness;
generally favourable outcome.
No antidote. Symptomatic care only:
sedatives or tranquillizers if necessary;
do not use the standard antidotes for atropine poisoning.