Rohisha: Benefits, Evidence & Safety

TL;DR

Rohisha (Cymbopogon martinii), also called palmarosa or rusa grass, is an aromatic Ayurvedic herb whose essential oil, rich in geraniol, inhibits bacteria, yeast, and parasitic worms in laboratory tests. However, no human clinical trials have tested Rohisha itself, so its therapeutic effects remain unproven.

(46 words. Sources: Pharmaceutics 2025, in vitro; Prashar et al. 2003, in vitro; Kumaran et al. 2003, in vitro.)

What it is

Rohisha is the Sanskrit name for Cymbopogon martinii (Roxb.) J.F. Watson, a tall, fragrant perennial grass in the grass family (Poaceae), native to the Indian subcontinent (WJPR galactagogue-plant survey). It is also known as rusa or rosha grass, and its distilled essential oil is sold internationally as palmarosa oil (Pharmaceutics 2025). The stems, leaves, and flowering tops are the parts harvested for the oil.

The oil's dominant compound is geraniol, a rose-scented monoterpene alcohol, typically making up roughly 65–80% of the oil, alongside geranyl acetate and linalool (Prashar et al., Phytochemistry 2003; Pharmaceutics 2025). Palmarosa oil is widely used in perfumery, cosmetics, and aromatherapy products (University of Zaragoza repository).

Traditional use

A peer-reviewed survey of galactagogue (milk-promoting) plants in Ayurveda texts lists Rohisha: Cymbopogon martinii (Roxb.) Wats: as a stanyajanana (lactation-supporting) herb, described in classical terms as pungent-bitter in taste, light-dry-sharp in quality, and heating in potency (WJPR survey). This is a traditional classification, not clinical proof: no trials have tested whether Rohisha affects human lactation, and nursing mothers should consult a clinician rather than self-treat.

What modern research says

Antibacterial activity (in vitro)

In a 2025 laboratory study, palmarosa essential oil inhibited clinical bacterial isolates taken from human skin and respiratory infections, with minimum inhibitory concentrations of 125–300 µg/mL against Streptococcus and Staphylococcus species and activity against Escherichia coli, Moraxella catarrhalis, and Morganella morganii. The whole oil was generally more potent than geraniol alone, and it affected cultured human liver cells less strongly than pure geraniol did (Pharmaceutics). This is petri-dish evidence only: it does not show the oil treats infections in people.

Antifungal action (in vitro)

Prashar and colleagues (2003) found that palmarosa oil at 0.1% completely stopped the growth of the yeast Saccharomyces cerevisiae in culture. The oil caused potassium leakage from the yeast cells, an effect attributed mainly to geraniol, and altered the fatty-acid composition of the yeast cell membrane (Phytochemistry). Again, a laboratory finding, not evidence of antifungal treatment in humans.

Anthelmintic action (in vitro)

Kumaran and colleagues (2003) tested palmarosa oil and its main constituent geraniol against the nematode Caenorhabditis elegans in vitro and found both had potent worm-killing activity. Geraniol, with an ED50 of 66.7 mcg/mL, was identified as the likely anthelmintic principle of the oil (Phytotherapy Research). A worm model in a dish is far from proof that the herb deworms people.

What the evidence does not support (yet)

No randomized human trials of Rohisha were found. The antibacterial, antifungal, and anthelmintic findings all come from laboratory cultures, and the traditional lactation use has no clinical validation. Claims that palmarosa oil treats infections, deworms, or boosts milk supply in humans are ahead of the data.

Safety & contraindications

Human safety data for Rohisha are lacking: no clinical trials have assessed it in people, so safety data is limited and you should talk to a clinician before use. Concentrated essential oils are for external or aromatherapy use, not for undiluted ingestion. Avoid use during pregnancy and breastfeeding unless a qualified practitioner advises otherwise.

FAQs

What is Rohisha?

Rohisha is the Ayurvedic name for Cymbopogon martinii, a fragrant grass native to India whose distilled oil, palmarosa oil, is rich in geraniol (WJPR survey). Ayurveda classifies it as a stanyajanana (lactation-supporting) herb, while modern laboratories study its oil for antimicrobial properties. It is distinct from lemongrass and citronella, though all belong to the same genus.

Is Rohisha the same as palmarosa?

Essentially, yes: palmarosa oil is the essential oil distilled from Rohisha grass (Cymbopogon martinii), and the plant itself is often called palmarosa in international trade (Pharmaceutics 2025). "Rohisha" is the Ayurvedic/Sanskrit name, "rusa grass" the common Indian name, and "palmarosa" the commercial oil name.

Does Rohisha kill bacteria?

In laboratory dishes, yes: palmarosa oil inhibited clinical isolates of Streptococcus, Staphylococcus, E. coli, and other bacteria at concentrations of 125–350 µg/mL (Pharmaceutics 2025). But petri-dish killing is not treatment: no human studies show that Rohisha or its oil cures bacterial infections, so it should not replace prescribed antibiotics.

Can Rohisha deworm people?

Unknown. The only anthelmintic evidence is a 2003 in-vitro study in which palmarosa oil and geraniol killed the model nematode C. elegans (Phytotherapy Research). That is not evidence of deworming in humans. Suspected worm infections need proper diagnosis and proven antiparasitic treatment from a clinician.

Is Rohisha safe during pregnancy?

Safety data is limited: talk to a clinician. Ayurvedic texts classify Rohisha as a lactation-supporting herb, but that traditional label is not safety evidence, and no human studies have evaluated it in pregnancy or breastfeeding (WJPR survey). Do not self-treat during pregnancy or while nursing.

Can I drink palmarosa essential oil?

No: essential oils are highly concentrated and should not be ingested undiluted. Palmarosa oil is used in perfumery, cosmetics, and aromatherapy (University of Zaragoza repository). Any internal use of the herb should only happen under the guidance of a qualified practitioner.

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.