The monk's-hood (Aconitum Napellus) is the plant from which the Pharmacopoeia preparations of this drug are made. They are aconitine - the active principle, - extract, tincture, liniment, and ointment.
Judging from the behaviour of horses, we may conclude that aconite applied to the more sensitive portions of the skin - the tongue and mouth generally - produces the tingling sensation so noticeable when brought in contact with similar parts on ourselves. The sensibility of the nerve ends being reduced by aconite, advantage is taken of the fact to employ liniments and ointments containing it with the object of allaying pain in acute rheumatism and painful swellings of various kinds, provided always that the skin is not abraded. When given internally, the effect upon the heart can be detected, in the diminished beat of the pulse and reduced numbers of respirations, in a few minutes. It is given in inflammation of the lungs and acute abdominal troubles, and is a constituent of some colic medicines. Its action should be carefully noted, and its use discontinued as soon as the desired effect upon the heart is made apparent in the pulse.