The fragrant flowers have five white to pinkish showy petals, each notched and reflexed, which form into close clusters (congested cymes) in the axils of leaves and at the tip of the stems.
The leaves are opposite, sessile, simple and entire; the stem is smooth and swollen at the joints. There are numerous bracts on the 4-foot decumbent and erect flower stalks. This glabrous perennial forms colonies from underground rhizomes. It is a member of the Pink Family, Caryophyllaceae.
A soapy lather will form when this plant is crushed and mixed with water, and has been used as soap since Greek times. All parts of this plant are poisonous if ingested. It spite of this, it has long been used in tea as a diuretic, laxative, and for many other ailments.