Botanical name: 

The full grown fruit, gathered green, of Conium maculatum, Linné (Nat. Ord. Umbelliferae). Europe and Asia; naturalized in the United States.
Common Names: Hemlock, Poison Hemlock, Spotted Hemlock.

Principal Constituents.—Five alkaloids of which the intensely poisonous liquid coniine (C8H17N) is most important; the others are: conhydrine (C8H17NO), pseudoconhydrine (C8H17NO), methyl-coniine (C9H19N), and ethyl-piperidine (C7H15N).
Preparation.—Specific Medicine Conium. 1/30 to 3 drops.

Specific Indications.—Nervous excitation and excessive motility, with or without pain; neuralgic pain; pain in the aged, and when there are cacoplastic deposits; gastric pain; nervousness and restlessness; mild maniacal excitement; persistent spasmodic or hacking cough; enfeebled state of the sexual organs, with late and scanty menstruation.

Action and Toxicology.—Conium does not affect the intellectual portion of the brain; and it acts but feebly on the spinal cord. It does, however, powerfully depress the peripheral motor endings, and in excessive amounts, the sensory terminals. Only very large doses affect the circulation and the respiration, when blood pressure falls and respiration becomes paralyzed. The latter is the cause of death by conium and is due to the combined results of depression of the respiratory center in the medulla and the nervomuscular paralysis of the muscles of respiration. Involuntary muscles are not affected by conium, nor is the heart-muscle or nerves appreciably affected.

Full doses of conium produce dryness of the throat and thirst, nausea, dizziness, sinking at the stomach, numbness, muscular relaxation, and depression of the circulation. Toxic amounts cause staggering gait, muscular heaviness and prostration, with failure of locomotion, ascending paralysis, difficult and labored articulation, dyspnea, dilated pupils, palpebral ptosis, and convulsions terminating in death. In rare instances coma ensues, but usually consciousness and the intellect remained unimpaired until death. The most marked symptoms of poisoning are the staggering gait, drooping eyelids, and ascending muscular prostration.

In poisoning by conium the emetic may be used, but it is preferable to repeatedly wash out the stomach by means of the stomach pump. Artificial respiration and heat are to be used, and strychnine, atropine and digitalis, as well as the diffusible stimulants, to sustain respiration and the circulation.

Therapy.—External. Locally applied extract of conium, or the powdered drug, relieves the pain of cancerous growths and ulcers. Locke advised, ℞. English Extract of Conium, 2 drachms; Petrolatum, 6 ounces. Mix. Apply locally.

Internal. Conium is a remedy for excessive motility and for pain. It also favors sleep, not because it is a hypnotic like opium, but because it relieves pain when that is the cause of the sleeplessness, or when due to an excitable action of the heart. It is also a remedy for the restlessness, with or without pain, associated with reproductive weakness, or due to sexual excesses. With this is a state of apathy, frequently frigidity in the female, and imperfect menstruation and leucorrheal discharges. The mentality is disturbed, often to the verge of mania. In such mild forms of nervous unrest and excitability small doses of conium will render good service.

Chorea is one of the incoordinate disorders that is sometimes relieved by conium, but not all cases respond to it. It has been advised in tetanus, but is insufficient except in doses which would be equally as dangerous as the disorder itself . It is better adapted to control the excessive movements of hysteria and mania, but in the former having little effect upon the psychic phase of the disorder. It has been used in teething, when twitching of the muscles is present, in laryngismus stridulus, also in whooping cough, but we have safer and more satisfactory remedies for these affections. Some cases of epilepsy due to masturbation have been relieved by conium, and it lessens the movements of paralysis agitans.

As a remedy for pain conium is fairly efficient, but it takes fair-sized doses to accomplish results. As the terminals of the sensory and motor nerves are directly affected by the drug, it is best adapted to peripheral pain with excessive mobility. Thus it relieves spasmodic neuralgia, neuralgia from carious teeth, ovarian neuralgia, and gastralgia. In gastric ulcer it is quite efficient and safe, while for relief of pain and to give rest it is a most important drug in gastric carcinoma. If there is much destruction of tissues it is less effective, but tends to keep the surrounding part obtunded and muscularly quiet, notwithstanding the statement that it has no control over involuntary musculature. In the intestines, however, it does not seem to lessen peristalsis, and is therefore not constipating, like opium and morphine. Conium has been used for so-called chronic rheumatism, especially in the aged, who complain of muscular soreness and joint pains, with loss of sleep. Given within bounds it may relieve and can do no harm. Sometimes it relieves pruritus, especially the senile form so distressing to old people and preventing rest and sleep.

Conium sometimes reduces glandular swellings. It frequently causes the disappearance of nodular masses in the axillary and mammary glands. By some it has been assumed that these are carcinomatous. There is no evidence of it having been of any service in dissipating ulcerating growths of the breast; therefore it is safe to assume that such nodules as are influenced by conium are probably not cancerous, but more than likely of a strumous character. At any rate we are not justified in delaying necessary measures by a long course of conium medication with uncertain prospects of relief in undoubted scirrhus of the breast. It may, however, be applied and be given to relieve pain even when a cure is not possible. It relieves the pain of swollen mammae during the menstrual periods and mitigates the distress of spasmodic dysmenorrhea.

In acute mania conium sometimes acts with great promptness. While occasionally subduing violent cases it is best adapted to those with mild excitability, great restlessness, with more or less wandering of the mind—much like the low delirium attending prostrating fevers. In fact, it is often useful, but must be carefully exhibited, in true typhomania, with subsultus tendinum. The field for conium in nervous disorders is still open to exploration, with the prospect of finding it adapted to a wide variety of nervous affections with excitation and muscular impressibility.

The Eclectic Materia Medica, Pharmacology and Therapeutics, 1922, was written by Harvey Wickes Felter, M.D.