Distribution and habitat: Throughout the tropics. In the plains of India from Uttar Pradesh to Assam, Madhya Pradesh, Andhra Pradesh, Tamil Nadu and Kerala.

Botany: An erect branched annual herb, 0.3 m- 0.9 m in height with quadrangular branches.

• Leaf: 1.2-2.5 cm, simple lanceolate, acute at both ends, glabrous, main nerves 4-6 pairs; petioles 0-6 mm long.
• Flower: Small, pale but blotched and spotted with brown and purple distant in lax spreading axillary and terminal racemes or panicles, the whole forming a large pyramidal paniculate inflorescence; Pedicels 0.8- 4 mm long, glandular-pubescent. Calyx- 3 mm long, lobes glandular pubescent, sepals equal, linear lanceolate, glandular pubescent; corolla rose coloured, 1 cm long, hairy out side, tube 5 mm long, filaments flattened in the upper part, ovary glabrous,  anthers bearded at the base.
• Fruit: Linear capsules, 20-30mmx3 mm, linear oblong, acute at both ends.
• Seed: Numerous, yellowish brown, .2 mm in Diameter, sub- quadrate.

Chemical constituents: 

• Leaves contain two bitter lactone substances andrographolide, kalmeghin,  homoandrographolide, andrographosterol and andrographone. 
• Kalmeghin is the active principle that contains 0.6% alkaloid of the crude plant. 
• The plant contains diterpenoids, andrographolide, 14-deoxy-11-oxo-andrographolide, 14-deoxy-11,12-dihydroandrographolide, 14-deoxy andrographolide and neoandrographolide. 
• The roots give flavones-apigenin-7,4-dio-O-methyl ether, 5-hydroxy-7,8,2’,3’-tetramethoxyflavone, andrographin and panicolin and a-sitosterol. 

Uses: Hyperdipsia, burning sensation, wounds, ulcers, chronic fever, malarial and intermittent fevers, inflammations, cough, bronchitis, skin diseases, leprosy, pruritis, intestinal worms, dyspepsia, flatulence, colic, diarrhoea, haemorrhoids and vitiated conditions of pitta. It is used to overcome sannipata type of fever, difficulty in breathing, hemopathy due to the morbidity of kapha and pitta, burning sensation, cough, oedema, thirst, skin diseases, fever, ulcer and worms. It is also useful in acidity and liver complaints. 

Formulations: Leaves contain homoandrographolide, andrographosterol and andrographone. Tiktakagheta, Gorocandi gulika, Candanasava, Panchatiktam kasaya etc. A preparation called “Alui” is prepared by mixing powdered cumin and large cardamom in the juice of this plant and administered for the treatment of malaria. It is also a rich source of minerals. 

Agrotechnology

Propagation: Seeds and cuttings 

Cultivation: The best season of planting  is May-June.  Seeds are to be soaked in water for 6 hours before sowing. Sowing is to be done at a spacing of 20 cm. Seeds may germinate within 15-20 days. 

Harvest: Flowering commences from third month onwards. At this stage, plant are to be collected, tied into small bundles and sun-dried for 4-5 days. Whole plant is the economic part and the yield is about 1.25t dried plants/ha.