Hyoscyamus seeds are obtained from biennial henbane, Hyoscyamus niger, Linn. (N.O. Solanaceae). The seeds are of a dark grey colour and very small in size, measuring slightly more than 1 millimetre in length. They are obscurely reniform in shape and flattened; under a strong lens the surface is seen to be regularly and distinctly reticulate. Each seed contains a coiled embryo embedded in an oily endosperm.
Constituents.—The chief constituent of the seeds is about 0.5 to 0.6 per cent. of alkaloid, consisting of hyoscyamine with a small proportion of hyoscine (Scopolamine). The seeds also contain about 20 per cent. of fixed oil.
Action and Uses.—Henbane seeds are used as a domestic remedy for toothache; the smoke obtained by heating the seeds on a hot plate is applied locally by means of a funnel, or a poultice may be made from the crushed drug. The expressed oil was formerly used externally, but is now almost obsolete.
Dose.—2 to 6 decigrams (3 to 10 grains).
The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.