Diamond flower commonly known as flat-top mille graines, is a species of plant in the family Rubiaceae. It is an annual herb with ascending or erect stems which are 4-angled. The plant has become a widely naturalized weed through the tropics and subtropics.
The plant is harvested from the wild for local use as a food, medicine and source of a dye. Linear-oblong or narrowly elliptic, almost stalkless leaves are 1-3.5 cm long and 1.5-7 mm wide, rough on margins. Midrib of the leaf is prominently visible. Flowers are borne in 2-8 flowered cymes in leaf axils. Flowers are white or faintly pinkish-purplish, on slender stalks 4-8 mm long. Flower tube is about 2 mm long, with 4 petals. Stamens are inserted just above the base of the tube. Capsule is about 2 x 2 mm, flattened at apex, slightly laterally compressed. Diamond Flower is found in found all over the tropical world. It is also found in the Himalayas.
The leaves are pounded, soaked in warm water and the liquid drunk to treat stomach disorders
They are used externally as a poultice to treat sores and sore eyes.
The entire plant is used in decoction as an anthelmintic, antirheumatic, depurative, diaphoretic, digestive, diuretic, febrifuge, pectoral and stomachic.
The juice of the plant is applied to the hands and feet to cool them when the patient has a fever.