Aconitum

All parts contain complex alkaloids, concentrated majoritary in root. Rate changes with seasons and geographic origin of plant (0,5 to 1,5 %). Main alkaloid is aconitine, but a lot of alkaloids are present : hypaconitine, mesaconitine, lycaconitine, neopelline, napelline, neoline... Main alkaloid is different for each species.

Intoxication :

It is exceptional in France where plant is rare, it is accidental or suicidal. In China, poisoning with aconite is not rare because different species growth in China and chinese people uses aconite to make drug. But chinese people reduces toxicity of tubers with boiling water before utilization. In Asia, poisoning with aconite is brought about bad preparation or guilty use...
In Occidental countries, poisoning is found in chinese diaspora, but also among occidental people using chinese medicine.
Toxic doses of aconitine to human are low (3 mg) : it is a violent poison. For 5 to 10 mg of aconitine survival is possible with effective treatement . For root, 2 to 4 g kill an adult.
Poisoning with ingestion is very fast, root is the very dangerous part of the plant. First symptoms are tinglings in mouth and tongue, then in face and limbs. Then anxiety attack, vertigo, weakness. Then, diarrhoea, heart troubles, and death with asphyxia. Consciousness is intact, aconitine only paralyses breathing and peripheral nervous system.
Treatment is difficult, antidote does not exist. Best treatment is fast evacuation of toxic substances, when it is possible and medical supervision in hospital. But prognosis is bad.

Aconites are traditional remedies. Today, in Occident, aconites are not used because they are toxic. But in Asia, aconites are traditionally used to make drugs.
Aconites are used to treat nevralgia and cough. Aconites are used in the past to poison arrows (hunt).