This section is from the book "An Experimental History Of The Materia Medica", by William Lewis.
Water-Parsnep. A genus of umbelliferous plants, growing in watery situations, with winged leaves, striated seeds, and a polyphyllous involucrum. Of these, a species has of late years come into frequent use under the name of Sium aquaticum, but this appellation equally suiting the three English kinds, it was a matter of doubt which of them was intended, and different opinions were given by botanists. The London college have at length determined the point by admitting into their catalogue the Sium nodiflorum Linn. Creeping water-parsnep, which is distinguished from the others by the reclining pofition of the leaves, and by the manner in which the umbels of flowers come out, chiefly from the axillae of the leaves.
It is a very common plant, often entirely covering the bottom of ditches. In cutaneous eruptions, and the cases termed scorbutic, the ex-preised juice of the water-parsnep has been given in the dose of three large spoonfuls twice a day to children, and three or four ounces every morning to adults, with great advantage. It is not nauseous, and is readily taken by children when mixed with milk. In these doses, it has no sensible effect on the head, stomach, or bowels, (a)