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.
All parts of the Chenopodium anthelminticum, wormseed or Jerusalem oak, abound in a highly odorous, volatile oil, upon which the anthelmintic virtues of the plant depend, and all, therefore, possess more or less efficacy; but the fruit, as the strongest and most uniform product, and that which keeps best, is the only part officinally recognized. The plant is an indigenous perennial herb, growing in most parts of the United States, but most abundantly in the southern section. it is also cultivated for medical purposes.
The fruit is globular, about the size of a pin's head or smaller, of a dull greenish-yellow or brownish colour externally, a strong, peculiar, disagreeable odour, and a bitterish, pungent, somewhat aromatic taste. if rubbed between the fingers, these grains lose an exterior coating which invests them, and have a shining black colour. The volatile oil, upon which their efficacy depends, is separated by distillation. it is officinal, and will be considered among the preparations. The seeds yield their virtues to alcohol, but only in a slight degree to water.
The fruit of Chenopodium ambrosioides is said sometimes to be mingled with or substituted for the genuine. But, as we want evidence of its equal efficiency, the mistake or fraud should be guarded against. The odour of this species is weaker than that of the other, and rather agreeable than offensive.
The effects of wormseed on the system are probably somewhat stimulant, especially upon the nervous centres; but its operation has not been satisfactorily investigated. it is certainly among our most efficient anthelmintics, though much less used than spigelia, probably in consequence of its unpleasant and adhesive odour, and disagreeable taste. it may be given in the shape of powder or volatile oil.
The dose of the powder, for a child two or three years old, is from twenty to forty grains, and four times the quantity for an adult. it may be given, mixed with molasses or syrup in the form of an electuary, in the morning before breakfast, and at bedtime, continued thus for three or four days, and then followed by a dose of caromel, or other brisk cathartic.
Oil of Wormseed (Oleum Chenopodii, U. S.) is of a light-yellow colour, deepening by age, lighter than water, and of a very strong, diffusive, and permanent odour, which is the greatest impediment to its use. in over-doses, it is probably capable of producing dangerous, if not fatal effects. From four to eight drops is the dose for a child from two to four years old. it may be administered in sweetened water, mucilage, or milk; but should always be diluted.