Last verified: April 2026

Kalmegh

कालमेघ -- Kalmegh -- "dark cloud; that which is dark as a monsoon cloud"

Kalmegh is among the most bitter herbs in the classical materia medica -- Bhavaprakasha documents it as Bhunimba (earth neem), reflecting its extreme bitterness. It is primarily documented for Jwara (fever), particularly the infectious and Pitta-type fevers, and for Yakritvikar (liver conditions). Modern pharmacological research on Andrographolide has confirmed its immunomodulatory, anti-inflammatory, and hepatoprotective properties.

Important noticeThis page documents what classical texts record. Not medical advice. Consult a qualified practitioner. Full disclaimer

Bhavaprakasha Nighantu, Guduchyadi Varga

Bhunimbo tikto ushno cha kaphapittavinaashakah / Jwaraghno deepano grahee -- Kalmegh (Bhunimba) is bitter, hot, and destroys Kapha and Pitta. It reduces fever, kindles digestive fire, and is a grahani (promotes intestinal absorption).

Classical documentation

Despite its Ushna (hot) Virya -- unusual for a Pitta-reducing herb -- Kalmegh's extreme bitterness and the Tikta Rasa's documented Pitta-purifying properties through Ama digestion make it appropriate for infectious Pitta-type conditions where Ama is the primary aggravating factor. Ashtanga Hridayam documents Kalmegh for Vishama Jwara (irregular fever), Krimiroga (parasitic infections), and Yakritvikar. The combination of Deepana (Agni-kindling) and Jwaraghna (fever-reducing) is the classical treatment principle for infectious fever -- treating both the Agni impairment and the Pitta-Ama fever simultaneously.

Andrographolide -- modern pharmacology

Andrographolide -- the primary diterpenoid lactone of Andrographis paniculata -- has been documented in multiple randomised controlled trials for upper respiratory infections, with meta-analyses showing significant reduction in symptom severity and duration. The WHO Monographs on Selected Medicinal Plants (Volume 2) includes Andrographis documentation. Multiple studies have documented immunostimulant effects through macrophage activation and lymphocyte proliferation.

Quality and adulteration

Kalmegh is frequently adulterated with other bitter herbs (Swertia chirata -- Kiratatikta -- is the most common substitute). API specifies minimum andrographolide content (1% in dried plant material) as the quality marker. TLC identification against andrographolide standard is the primary authentication method.