What is Kushta?

Kushta (also spelled Kushtha) is the dried root of a Himalayan plant, Saussurea costus. Ayurveda uses it as a single herb, not as part of a mixed formula. It is taken mostly for gas and slow digestion, coughs and wheezing, itchy skin and sore joints.

The name causes real confusion, and getting it wrong matters. In Unani medicine, "Kushta" means something quite different. It is a calcined (fire-treated) metal or mineral powder that can hold lead, mercury or arsenic.

In older Ayurvedic texts, "kushtha" is also the name of a group of skin diseases. This page is about the Saussurea costus root only.

Evidence verdict: the root has a deep place in several healing systems. But we could not find good human trials of this root on its own. So its effects in people stay unproven.

Long use by healers tells you what people have done for years. It is not proof that a remedy works. That holds for everything on this page.

How does Kushta work?

Nobody has shown how Kushta works in the human body. The ideas below come from lab dishes and animal studies, not from people.

The oily part of the root holds sesquiterpene lactones (a family of plant compounds). The main two are costunolide and dehydrocostus lactone.

In lab work, these calm the signals that drive swelling in cells. They also relax strips of gut and airway muscle taken from animals.

Ayurvedic theory describes the herb in its own terms. Kushta is said to be warming and sharp, to move stalled digestion, and to clear kapha (the heavy, mucus-linked quality) from the chest.

That is a traditional guide for picking the herb. It is not a tested account of what happens in the body.

What forms does Kushta come in?

Kushta is sold in a few forms, and they are not the same thing.

Dried root, whole or in slices, is simmered in water to make a decoction (a water extract). Root powder, called churna, is the form classical texts use most. Capsules or tablets of the powder turn up in modern supplement ranges.

It is also one part of many mixed Ayurvedic and Unani products. Pastes of the powder, mixed with water or oil, are put on skin and joints.

Costus root oil is the strong essential oil. Perfume makers use it, and it is limited as a fragrance because it sets off allergy so easily. It is for outside and industrial use only — do not swallow it.

One practical point: Saussurea costus is an endangered plant, listed on CITES Appendix I. Legal supply is small, so sellers often swap in other roots.

Where it comes from:

Kushta is one of the oldest named drugs in Indian medicine. It appears in the Charaka Samhita and Sushruta Samhita, texts roughly 2,000 years old. There it is used for digestion, cough and skin complaints.

It travelled widely. The same root is ru rta in Tibetan medicine and qust in Unani practice. In Chinese medicine it is mu xiang, a standard remedy for belly pain and bloating.

Costus root also reached the Greek and Roman world by trade. There it was burned as incense and used in perfume.

Too much wild picking put the plant on the CITES endangered list. Grown stock now supplies most legal trade.

What does Kushta help with?

• Gas, bloating and slow digestion: This is the most consistent traditional use, shared by Ayurvedic, Unani and Chinese practice, where the root is given before meals for a heavy, gassy stomach. Laboratory work shows the oil relaxes strips of animal gut muscle, which fits the traditional picture. We found no human trial testing the root alone for bloating or indigestion.
• Cough and wheezing: Classical Ayurvedic texts class Kushta among remedies for cough and breathlessness, and it appears in many old asthma formulas. Animal tissue studies show some relaxation of airway muscle. There is no trial evidence that it helps asthma or bronchitis in people, and asthma is dangerous when undertreated — never swap a prescribed inhaler for it.
• Itchy skin complaints: Traditionally the powder is applied as a paste for itching and long-standing rashes. This is worth extra care, because the root's own compounds are known skin sensitisers — they cause allergic rash in a meaningful number of people. Evidence of benefit in humans is absent; evidence of allergic reaction is well documented.
• Joint and muscle pain: Kushta is a common ingredient in Ayurvedic oils massaged into stiff or painful joints. Cell studies show its lactones reduce inflammatory signalling. No human trial has tested whether rubbing it on or taking it by mouth reduces joint pain.
• Intestinal worms: Old texts list it as an anthelmintic (worm-expelling) drug. Some laboratory studies kill worms in a dish. Modern deworming medicines are cheap, tested and reliable, so this use is historical interest rather than practical advice.
• Period pain: Traditional use includes bringing on delayed periods and easing cramps. The same property is the reason it is not considered safe in pregnancy. There is no human evidence for either benefit or dose.

Which foods are rich in Kushta?

Kushta is a medicinal root, not a nutrient, and it is not part of any normal diet; its oil appears only as a trace flavouring or fragrance in some manufactured products.

What are the side effects of Kushta?

• Itchy red rash after handling the root, powder or oil
• Allergic skin reaction in people sensitive to daisy-family plants
• Nausea or stomach upset
• Burning feeling in the mouth or throat
• Loose stools
• Headache

Good to know:

The best-documented problem is allergic contact dermatitis — an itchy rash where the plant touched your skin. Costus root oil is a well-known fragrance allergen, which is why its use in cosmetics is restricted.

Stomach upset and nausea are reported with the powder taken by mouth, usually mild and settling when you stop. Because no proper safety trial exists, rarer or delayed effects may simply be unrecorded rather than absent.

Stop taking it and get advice if you develop a spreading rash, swelling of the face or lips, or trouble breathing.

How much Kushta should you take?

• Recommended daily: There is no evidence-based dose. No good human trial has set one. What follows is traditional use, not advice. Ayurvedic and Unani texts use 1 to 3 grams of dried root powder a day. That is split into two or three doses of about 0.5 to 1 gram. Each dose is taken with warm water or honey. For a decoction, a few grams of chopped root are simmered in water. Do not swallow the essential oil at any dose. If you use Kushta at all, use the smallest traditional amount. Ask an Ayurvedic expert or your doctor to oversee it.
• Best time of day: For digestion, it is taken before or between meals. For a night cough, it is taken in the evening. Split the daily amount across two or three doses rather than taking it all at once.
• With or without food: It is traditionally taken shortly before food, with warm water. If it upsets your stomach, take it with food instead, or stop.
• Time to effect: Unknown, since it has not been measured in people. Traditional use expects help with digestion within a day or two. Skin and joint uses are expected to take several weeks.
• How long to take it: Keep any course short — two to four weeks at most. Then stop and take stock. Daily use over long stretches has never been checked for safety. Has your problem not clearly improved in two weeks? Then stop, and see a doctor rather than raise the dose.