Rhubarb and Its Laxative Properties

The medicinal parts are the dried underground parts free of the stem remnants, the smaller roots, and most of the root bark in the dried form. Garden rhubarb is Rheum ponticum. 

The inflorescence is an erect panicle foliated to the tip. The flowers consist of narrow, red, pink, or whitish yellow petals, which are curved and located far back in the mature flowers to facilitate wind pollination. The fruit is red-brown to brown, and oval. It is angular, about 10.2 to 7.8 mm wide and usually has scarious wings. The nutlet is 6 to 10 mm long and 7 mm in diameter. 

The plant is a large, sturdy herbaceous perennial. The stem grows to over 1.5 m high. The leaves are orbicular-cordate, palmate-lobed, somewhat rough on the upper surface, or smooth and three- to five-ribbed. The lobes are oblong-ovate to lanceolate, dentate or pinnatisect. The root system consists of a tuber, which after a number of years measures 10 to 15 cm in diameter and has arm-thick lateral roots. 

The plant is indigenous to the western and northwestern provinces of China and is cultivated in many regions around the world. The main producers are China and Russia. 

Rhubarb consists of the dried underground parts of R. paimatum, R. officinale, or of both species. Stem parts, roots, and most of the bark are removed from the rhizomes. 

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