This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Spina Cervina Pharm. Lond. Rhamnus catbarticus five Spina cervina Pharm. Edinb. Rbamnus catbarticus C. B. & Linn. Spina infectoria et cervifpina quibusdam. Buckthorn: a prickly bush, or low tree, common in hedges: with oval pointed leaves; producing in June small greenish flowers; and about the beginning of October ripening its black berries, which contain a dark green juice, with four seeds in each. The berries of the black alder and dogberry tree, which are frequently, in our markets, mixed with or substituted for those of buckthorn, may be distinguished, by their juice having no greenness, and by their containing only one or two seeds.
Buckthorn berries have a faint unpleasant smell, and a bitterish, acrid, nauseous taste. They operate briskly by stool; and occasion, at the same time, a third and dryness of the mouth and throat, and not unfrequently severe gripes, especially if water-gruel or other soft diluents are not freely drank soon after taking them. The dose is said to be, about twenty of the fresh berries in substance; twice or thrice that number in decoction; a dram, or a dram and a half, of the dried berries; an ounce of the expressed juice; or half an ounce of the rob or extract obtained by infpififating the juice. Among us they have been employed only in the form of a syrup, in which they seem to operate less unkindly than in any other, and which is given by itself in doses of three or four spoon-fuls, or mixed in smaller quantities with other cathartics. The college of Edinburgh directs the syrup to be prepared by boiling the depurated juice with sugar to a due consistence: that of London adds a little ginger, and pimento, with a view to cover in some degree the ill flavour of the buckthorn: but notwithstanding this improvement of the medicine, it is still so unpleasant and so churlish, that it has now almost fallen into difuse.