Ayurveda
MustaCyperus rotundus
Nut grass tuber, used in Ayurveda for diarrhea and weak digestion. The antidiarrheal work is laboratory and mouse research (250 and 500 mg/kg); no human gut trial found.
- Botanical name
- Cyperus rotundus
- Part used
- tuber (the underground rhizome tuber)
- Also called
- Sanskrit Musta, Mustaka, Bhadramusta; Hindi Motha, Nagarmotha; Nut grass, Nutsedge, Saad-e-Kufi (Unani)
- Used in
- Ayurveda
- Taken for
- Loose stools and diarrhea, Indigestion, Cramping and pain
- Sold as
- powder, decoction, capsules, essential oil
What musta is
Musta is the dried tuber of Cyperus rotundus, a perennial sedge (family Cyperaceae). A 2015 review notes that it is also one of the most widespread and damaging agricultural weeds in tropical and subtropical regions, which is why it is known in English as nut grass; an Ayurvedic college monograph describes it as common in rice fields, low lands and water-logged places across India. The small brown tubers are dug up, dried and used as a powder, a decoction or a capsule, and the essential oil is also distilled.
The monograph records three plants traded as musta: Nagara musta (Cyperus scariosus), Bhadra musta (Cyperus rotundus) and Kaivarta or Jala musta (Cyperus esculentus), so a label that says only “musta” may not specify which. Most of what is known about musta and the gut comes from laboratory work and from mice; we found no human gut trials.
What the traditions use it for
Ayurveda (about Ayurveda)
An Ayurvedic college monograph gives musta a bitter, pungent and astringent taste (rasa), light and dry qualities (guna), a cooling potency (virya) and a pungent after-digestion effect (vipaka). The tradition says it calms kapha and pitta, two of its three governing principles (doshas), and lists its actions as dipana-pachana (kindling and aiding digestion), grahi (binding, used for loose stools) and lekhana (scraping, in the tradition’s language a drying, reducing action). Charaka groups it with the lekhaniya, thirst-quenching, itch-relieving and milk-purifying drugs.
The indications listed include fever, intestinal worms, thirst, atisara (acute loose stools), grahani (a chronic condition of poor digestion with erratic stools), cough and skin disease. The monograph says it is used in anorexia, vomiting, indigestion, sprue and diarrhea, and that a mixture of musta, karkatshringi and ativisha, the Balsanjivani Churna, is given for digestive disorders in infants. It gives the powder as 3 to 6 g and a decoction as 50 to 100 ml.
The constituents
The tubers hold sesquiterpenes, including cyperene, cyperol, cyperotundone, rotundone and selinene, along with beta-sitosterol, according to the Ayurvedic monograph. A 2015 review attributes antidiarrheal, antibacterial, anti-inflammatory and many other activities to the tuber’s essential oils, phenolic acids and flavonoids. Three laboratory findings bear on the gut. A tuber decoction showed activity against Giardia in a dish and reduced bacterial adherence to and invasion of gut-lining cells, without marked direct antimicrobial activity. A crude extract relaxed rabbit gut muscle through what the authors describe as calcium-channel blockade similar to verapamil. A methanol extract reduced castor-oil diarrhea in mice. None is a human result.
The human evidence
We could not find a human trial of musta for diarrhea, indigestion or any other gut condition. A 2015 review of its traditional uses and pharmacology concludes that future studies should confirm its clinical activities and safety in people before it is used as a therapeutic agent.
The diarrhea evidence is from animals and tissue. In 2006, a methanol extract of the rhizome given by mouth at 250 and 500 mg/kg showed significant antidiarrheal activity in castor-oil-induced diarrhea in mice; of the fractions tested at 250 mg/kg, the petroleum ether and residual methanol fractions kept the activity, the latter more strongly, and the ethyl acetate fraction had none. In 2011 a tuber decoction was tested against diarrhea-causing organisms: it showed antigiardial activity, cut bacterial adherence to and invasion of gut-lining cells, and affected cholera toxin and the heat-labile toxin of E. coli. The authors concluded that it works by mechanisms other than killing the pathogen directly. In 2018 a crude extract relaxed spontaneous and potassium-induced contractions of rabbit small intestine, which the authors say supports the folk use for diarrhea and dyspepsia.
Mouse doses in milligrams per kilogram do not convert to a human amount, and none of these experiments has a human counterpart that we could find.
| Study | Dose | What it found |
|---|---|---|
| Mouse study of a methanol rhizome extract in castor-oil-induced diarrhea PMID 16376024 | 250 and 500 mg/kg by mouth (mice) | Significant antidiarrheal activity; petroleum ether and residual methanol fractions kept the effect, ethyl acetate fraction did not |
| Laboratory study of a tuber decoction against diarrhea-causing organisms and toxins PMID 21713044 | Hot-water decoction (in vitro) | Antigiardial activity; less bacterial adherence and invasion in cells; affected cholera toxin and E. coli heat-labile toxin |
| Rabbit jejunum tissue study of a crude extract PMID 29348090 | Crude extract (isolated tissue) | Relaxed spontaneous and potassium-induced contractions; calcium-channel blockade similar to verapamil |
| Review of traditional uses, phytochemistry and pharmacology of C. rotundus PMID 26297840 | Not applicable (review) | Lists antidiarrheal activity among many; calls for studies confirming clinical activity and safety in humans |
Doses, in trials and in practice
Ayurvedic college monographs give the traditional amounts as 3 to 6 g of tuber powder or 50 to 100 ml of a decoction. No human trial dose exists, because no human gut trial exists. The mouse experiment used 250 and 500 mg/kg of a methanol extract, which are animal doses and not a guide for people, and the laboratory studies used a decoction and a crude extract without stating a human equivalent. The sources we read give no traditional dose for children beyond naming the infant formula Balsanjivani Churna.
The amounts above are what trials and pharmacopoeias record, not a dose for you; your medicines and conditions change the answer, and a clinician or pharmacist who knows them is the person to ask.
What is known about safety
We found no human safety data for musta in the sources we read, and the 2015 review calls for studies confirming safety before therapeutic use. No pregnancy or breastfeeding data turned up either. Two points concern products. Several plants are traded under the name musta, as noted above. And published findings about Ayurvedic medicines in general include a 2008 JAMA study that found lead, mercury or arsenic in 20.7% of 193 Ayurvedic products bought online, with metals in 40.6% of mineral-and-metal preparations against 17.1% of the others; that study concerns those products, and musta tuber powder was not analyzed separately in it.
Where it meets prescription medicines
We found no interaction study of musta. In rabbit gut tissue a crude extract acted like verapamil, a calcium-channel blocker, which is a laboratory observation; whether this matters for people who take calcium-channel blocking medicines has not been studied. The tradition’s binding action (grahi) is a classical description, and no measurement of it alongside other medicines was in our sources.
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Questions people ask
Has musta been tested for diarrhea in people?
We could not find a human trial. The diarrhea evidence is a mouse study with a methanol extract (250 and 500 mg/kg), a laboratory study of a tuber decoction, and a rabbit gut-tissue study.
What does Ayurveda say musta does?
A college monograph classes it as bitter, pungent, astringent, light, dry and cooling, and lists atisara (acute loose stools), grahani (chronic poor digestion with erratic stools), indigestion, anorexia and worms among its uses. These are the tradition’s statements.
Is musta the same as nut grass?
Yes, nut grass is the English name for Cyperus rotundus, a sedge that is also a widespread weed. The Ayurvedic monograph notes that two other Cyperus species are traded as musta, so the botanical name matters.
How did the decoction study say musta works?
The authors found it did not kill the bacteria tested but reduced their adherence to and invasion of gut-lining cells and affected cholera toxin, and concluded it acts by mechanisms other than direct killing. It also showed activity against Giardia in the dish.
What doses are traditional?
The monograph gives 3 to 6 g of tuber powder or 50 to 100 ml of a decoction. These are traditional amounts, not trial doses.
Sources
- Uddin SJ et al., "Antidiarrhoeal activity of Cyperus rotundus", Fitoterapia 2006;77(2):134-136 pubmed.ncbi.nlm.nih.gov/16376024
- Daswani PG et al., "Studies on the activity of Cyperus rotundus Linn. tubers against infectious diarrhea", Indian J Pharmacol 2011;43(3):340-344 pubmed.ncbi.nlm.nih.gov/21713044
- Hussain M et al., "Pharmacological validation of the folkloric uses of Cyperus rotundus L. in different ailments: An in vivo and in vitro research", Pak J Pharm Sci 2018;31(1):95-102 pubmed.ncbi.nlm.nih.gov/29348090
- Pirzada AM et al., "Cyperus rotundus L.: Traditional uses, phytochemistry, and pharmacological activities", J Ethnopharmacol 2015;174:540-560 pubmed.ncbi.nlm.nih.gov/26297840
- Shri Dhanwantry Ayurvedic College & Hospital, Chandigarh, Dravyaguna monograph: Musta www.sdach.ac.in/about-dravyaguna-vigyan/dravyaguna-vigyan-blogs/musta
- Saper RB et al., "Lead, mercury, and arsenic in US- and Indian-manufactured Ayurvedic medicines sold via the Internet", JAMA 2008;300(8):915-923 pubmed.ncbi.nlm.nih.gov/18728265