This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Rapa sativa rotunda C. B. Braffica Rapa Linn. Turnep; a plant with a round root; jagged leaves, rude to the touch; tetrapetalous flowers, commonly yellow; and small round smooth reddish or blackish seeds lodged in long pods. The garden turnep is supposed to be a variety produced by culture from the smaller sort which grows wild in sandy grounds in some parts of England. It is biennial.
Turneps are accounted a salubrious food; demulcent, detergent, somewhat laxative and diuretic; but liable in weak stomachs to produce flatulencies, and prove difficult of digestion: the liquor pressed out from them after boiling, is sometimes taken medicinally, in coughs and disorders of the bread. The seeds have been accounted alexipharmac or diaphoretic: they have no smell, but discover to the taste a mild acrimony, seemingly of the same nature with that of mustard seed, though far weaker.