Skip to content
Soul of Herbs
← Back to herbs

Limnophila aromatica

Rice paddy herb

Generally recognised as safe

Other names: Rice paddy herb, Ambulia

A Vietnamese paddy herb with an aroma between lemon and cumin.

A small aquatic perennial with whorled leaves and tiny pale-pink flowers; the aerial parts carry an aroma between lemon, cumin, and mint, and are added to Vietnamese sweet-sour soups and fish dishes.

Family
Plantaginaceae
Plant type
Aquatic perennial
What the safety levels mean (expand legend)
  • Generally recognised as safe. Often a common herb with reasonable harvest and use; still read the specific warnings on the card.
  • Information. Primarily informational — details in the text and warnings below matter most.
  • Caution. Needs extra care (dose, duration, sensitive groups, interactions).
  • Risky. Significant risks — verify sources, contraindications and professional guidance.
  • Not for home experimentation. Not suitable to experiment with at home without knowledge and certainty.
  • High risk for internal use. Particular risk with internal use (e.g. alkaloids); avoid prolonged or irresponsible dosing.
  • Not specified. Level not filled in yet — rely on individual warnings and links below.
Rice paddy herb — plant habitus (Wikimedia Commons).

Photograph on Wikimedia Commons (CC BY-SA 2.0).

Plant habit

Quick overview

A practical summary; details are in the sections below.

Safety grade
Generally recognised as safe details
Scientific sources on the card
Yes — sources are listed with claims Science section
When and what to harvest
  • Leaf — January–December
Full harvest section
Processing methods

Culinary use

All methods and recipes on the card
Topics and symptoms

Bloating & gas, Digestion, Kidneys & urinary comfort

Topics section, Symptoms overview

Identification and mix-ups

Aquatic to marsh herb in Plantaginaceae, stems 30–70 cm, often branched with a reddish hue. Leaves sessile, in whorls of 4–6 (sometimes opposite), oblong-lanceolate to linear, 2–6 cm, with toothed margins. Flowers pink to pale purple, solitary or in whorled inflorescences. Citrus-cumin scent when crushed.

Possible mix-ups and risks

Confusion with Limnophila chinensis (L. aromatica is sometimes treated as its subspecies) and L. aromaticoides (now a synonym of L. aromatica). They are distinguished mainly by the number of leaves per whorl; plants with 6–8 or more leaves per whorl are not true L. aromatica. No toxic lookalike is documented.

Similar herbs

No related herbs are linked yet.

Topics and symptoms

More topics are in the symptoms and topics overview.

Sources

Geographic occurrence

  • Viet Nam

    Common (expected wild occurrence in the region)

Harvest

  • LeafJanuary–December

    year-round

    Region: Viet Nam

    Notes: Young shoots from shallow paddy water or ditches.

Storage

  • Refrigeration(Leaf)

    Fresh stems keep 3–5 days in the fridge in a glass of water; they wilt very fast. Not dried — the scent vanishes on drying; can be chopped and frozen.

    Moisture:
    An aquatic herb — without water it wilts within hours.

Processing methods on this herb card

  • Culinary use(Leaf)Suitability: High suitability

    Cooking, baking, seasoning as food — general category without therapeutic claims.

    Full method description (from the catalogue)

    Culinary use covers herbs as ingredients in dishes, drinks, or spice mixes. This overview does not evaluate medicinal effects — only reminds you about species intent, allergies, and heat treatment where needed (e.g. some fruits or plant parts).

    Combining with alcohol, sugar, or long cooking changes outcomes; verify culinary sources.

    Traditional context for this method: yes·Scientific context for this method: no

    Canh chua — sour soup with rice paddy herb

    About 30 minBeginnerScience profile

    Open recipe →

Traditional / spiritual use

Kept separate from science — entries are cultural or symbolic, not medical advice.

  • From the rice paddy to the whole world

    General

    Traditional useFolk useHerbal lore

    Limnophila grows in the flooded paddies of southern Vietnam, and its name rau om, 'herb of the field', says as much. Folk medicine of the Mekong Delta boiled it for fever and urinary complaints and laid it on wounds; it spread across the world after 1975 with Vietnamese refugees, who began growing it in California, Texas and Australia, where today it also lives in aquaria. A record of tradition.

    Form:
    a rice-field herb that arrived with Vietnamese refugees
    Claim strength:
    Tradition
    Source note:
    Vairappan CS et al. (2014), J Trop Biol Conserv 11:41–48 (ethnobotanical introduction); Vietnamese folk medicine of the Mekong Delta.

Scientific notes

Each claim lists a study type and a source (URL or DOI) where available. Dose notes from the literature are informational only.

How to read evidence strength and study type labels

Labels summarise how the catalogue entry is tagged — they are not a medical verdict on efficacy. For every row, read the summary, limitations and source link.

Evidence strength

Evidence level not specified
The author did not grade the record; judge from the summary, limitations and source link.
Narrative / orientational literature
Descriptive or expert literature without controlled group comparison — context rather than proof of effect.
Weak evidence
Study or conclusion with major methodological limits; treat only as a pointer for further reading.
Preliminary findings
First or smaller studies — interesting direction, not the final word on efficacy or safety.
Moderate strength of evidence
Moderate strength by study design; sample and context limits still apply.
Stronger evidence
Stronger design or consistency of results within the study's stated limits.
Review article
A review summarises multiple sources; quality depends on review method and field.

Study type

Narrative / expert text
Expert text or overview without a classical study design.
In vitro study
Cell culture or test-tube experiment — does not show an effect in the body.
Animal study
Animal model — transfer to humans is not automatic.
Observational study
Observing groups without random treatment assignment; confounding is possible.
Clinical trial
Human clinical trial; sample size and control group matter.
Randomised controlled trial
Randomised controlled trials are among the stronger designs when well conducted.
Review study
A review aggregates multiple papers — quality depends on selection rules.
Systematic review
Systematic review with explicit search and selection methodology.
Meta-analysis
Statistical pooling of studies; outcome depends on input data and heterogeneity.
Regulatory assessment / monograph (EMA, WHO…)
Regulatory body summary for a herbal product — different context from a single RCT; often about products, not home tea.
Expert monograph (herbal preparations)
Structured literature summary for a plant or drug — quality depends on author and edition year.

Images

The main photo is in the card header. More images will appear here when available.

Safety

What the warning types mean

The type on each warning helps group themes — it does not replace the separate severity badge.

Internal use
Risks from swallowing, extracts, duration of use or concentration for internal use.
Interactions / medicines
Possible effect on medicines or concurrent treatment — check sources and a professional.
Raw plant parts
Raw, unripe or poorly prepared plant parts can be dangerous.
Toxins and regulation
Toxic constituents or regulated compounds (e.g. in distillates).
Contact with the plant
Skin or mucosa irritation from contact with fresh plant or sap.
Allergy
Allergic reactions, often linked to family sensitisation.
Harvesting and contamination
Contamination, species mix-ups or harvesting from unsuitable places.

No structured safety records yet.