This section is from the book "A Treatise On Therapeutics, And Pharmacology Or Materia Medica Vol2", by George B. Wood. Also available from Amazon: Part 1 and Part 2.
Gelsemium, which may now be received as the ordinary designation of the medicine, is the root of Gelsemium sempervirens, the yellow or Carolina jasmine of our Southern States. The medicine has been admitted into the secondary catalogue of the U. S. Pharmacopoeia, and, judged of by the extent to which it is used throughout this country, it might, perhaps, be considered as worthy of a place in the primary. For the physical and chemical properties of the root, I must content myself with referring to the U. S. Dispensatory. its effects on the system appear to be such as entitle it to a place among the nervous sedatives in our classification; but, never having had any experience with the medicine, I am not authorized to speak authoritatively on the subject.
In moderate doses gelsemium is said to cause agreeable sensations of languor with muscular relaxation. Largely taken, it diminishes the frequency and force of the pulse and the frequency of respiration, and, acting on the nervous system, causes vertigo, dimness or disorder of vision, dilated pupil, general muscular debility, and insensibility to pain, but with neither delirium nor stupor. it commonly begins to act in half an hour, and ceases after one or two hours, leaving no unpleasant effect. Originally employed only as a vermifuge, it was accidentally found to possess remarkable sedative properties in febrile disease, and came into extensive use as a domestic remedy, and among the so-called eclectic practitioners, before it came to the knowledge of the regular profession. it is given as an arterial sedative in the different idiopathic fevers; in the phlegmasiae, especially pneumonia, pleurisy, and acute rheumatism; and, with reference to its depressing influence on nervous irritation, in epilepsy, chorea, hysteria, and neuralgia. it has also been recommended in gonorrhoea. Though efficient in the form of infusion, it is generally used in that of a tincture, which may be made in the proportion of four ounces of the fresh root to a pint of diluted alcohol. The dose of this tincture is from twenty to fifty drops.