Kushtha (Costus Root): Uses, Evidence & Conservation

TL;DR

Kushtha is the aromatic root of Saussurea lappa (costus), a Himalayan Asteraceae used in Ayurveda for digestive, respiratory, and skin complaints. Nearly all pharmacology is preclinical: no controlled human trial was identified. The species is CITES Appendix I-listed; wild collection is banned in India while cultivation is strictly regulated. Its sesquiterpene lactones can cause skin sensitization in susceptible people.

What it is

Kushtha is the dried aromatic root of Saussurea lappa (Decne.) C.B. Clarke (syn. Saussurea costus), family Asteraceae: a tall perennial herb indigenous to the Himalaya of India, Pakistan, and China at 2,500–3,500 m altitude, whose stout root has a characteristic strong odour (Zahara et al., Asian Pac J Trop Med 201460204-2)). The drug is known as radix saussureae lappae and is marketed as costus root: in India as Kuth (Zahara et al.60204-2)). Its chemistry is dominated by sesquiterpene lactones, chiefly costunolide and dehydrocostus lactone (Zahara et al.60204-2)).

Conservation status matters here. S. lappa is critically endangered: it was listed in CITES Appendix II in 1975 and up-listed to Appendix I in 1985 (Zahara et al.60204-2)). A conservation review reports it as CITES Appendix I-listed and under India's Wildlife Protection Act (Schedule VI): wild collection is banned in India, while cultivation and marketing require permission: so cultivated trade exists under regulation, not a total trade ban (Journal of Threatened Taxa). It is commercially cultivated from Kashmir to Garhwal and in China. Any legitimate supply must come from documented cultivation.

Traditional use

S. lappa is used in Ayurveda, Unani, Siddha, Tibetan, and Chinese medicine. Ayurvedic physicians use root preparations for cold, flatulence, cough, asthma, chronic skin diseases, rheumatism, gout, headache, and itching. The roots are described as carminative, anthelmintic, analgesic, and emmenagogic (Zahara et al., Asian Pac J Trop Med 201460204-2)). It is also a traditional remedy for skin conditions including scabies, ringworm, and leprosy, and the fragrant root oil is valued in perfumery (Zahara et al.60204-2)). These are traditional claims, not clinical proof: the human evidence is assessed separately below.

What modern research says

Everything else: preclinical only

All other reported activity comes from laboratory and animal work: costunolide and dehydrocostus lactone induced apoptosis in human leukemia, prostate, and liver cancer cell lines. Ethanolic extracts showed anti-inflammatory effects in rodent models; root extracts were hepatoprotective in mice and antidiarrheal in rats (Zahara et al.60204-2)). The reviewers are explicit about the limits: "the quality of the evidence is limited" and "more in vitro, clinical and pathological studies are required" before medicinal applications can be validated (Zahara et al.60204-2)). Claims that Kushtha treats cancer, ulcers, or infections in people are unsupported.

Safety & contraindications

Dedicated human safety data are lacking; the reviewers stress that active constituents, pharmacokinetics, and bioavailability "are not known with sufficient detail or assurance" (Zahara et al., Asian Pac J Trop Med 201460204-2)). Sesquiterpene lactones can sensitize susceptible individuals: costus root oil was among the oils showing more than 2% positive patch-test reactions in a review of essential-oil contact allergy (de Groot & Schmidt, Dermatitis 2016), and occupational sensitization with systemic allergic dermatitis from costus resinoid and related sesquiterpene lactone exposure has been reported (PubMed). Because the root is traditionally described as emmenagogic, avoid use during pregnancy as a precaution. Wild-harvested material may carry quality and contamination risks: another reason to insist on cultivated, quality-tested sources.

FAQs

What is Kushtha?

Kushtha is the dried aromatic root of Saussurea lappa (syn. S. costus), a Himalayan member of the daisy family (Asteraceae), marketed internationally as costus root and in India as Kuth (Zahara et al., Asian Pac J Trop Med 201460204-2)). Its main studied constituents are the sesquiterpene lactones costunolide and dehydrocostus lactone (Zahara et al.60204-2)).

Does Kushtha help digestion?

No controlled human trial has tested it. Traditional Ayurvedic use for flatulence and digestive complaints rests on preclinical findings only: the pharmacology is almost entirely laboratory and animal work (Zahara et al., Asian Pac J Trop Med 201460204-2)).

Is Kushtha an endangered species?

Yes. Saussurea lappa is critically endangered and CITES Appendix I-listed (up-listed from Appendix II in 1985). Wild collection is banned in India under the Wildlife Protection Act (Schedule VI), while cultivation and marketing require permission (Journal of Threatened Taxa). It is commercially cultivated: any legitimate supply must document cultivated sourcing.

Does Kushtha fight cancer?

No: not in people. Costunolide and dehydrocostus lactone killed or inhibited various human cancer cell lines in laboratory studies, and reviewers call them "latent anticancer agents" for drug development (Zahara et al., Asian Pac J Trop Med 201460204-2)). Cell-line cytotoxicity is not cancer treatment; there are no human cancer trials, and presenting it as such would be misleading.

Is Kushtha safe?

Human safety data are essentially absent, and constituents, pharmacokinetics, and bioavailability are poorly characterized (Zahara et al., Asian Pac J Trop Med 201460204-2)). Its sesquiterpene lactones can cause skin sensitization in susceptible individuals (de Groot & Schmidt, Dermatitis 2016): avoid it in pregnancy (it is traditionally emmenagogic) and insist on quality-tested, cultivated material.

Sources

Disclaimer

This article is for educational purposes only and is not medical advice. Herbal products can interact with medications and are not suitable for everyone. Talk to a qualified healthcare practitioner before use — especially if you are pregnant, breastfeeding, managing a medical condition, or taking prescription medicines.