Khella Herb (Ammi visnaga): Benefits, Dosage, Safety & Evidence

Frequently asked questions

How does Khella work for asthma and kidney stones?

Khella contains khellin and visnagin, furochromone compounds that act as calcium channel blockers and smooth muscle relaxants. These compounds inhibit bronchial and ureteral smooth muscle contractions, explaining their traditional use for asthma and kidney stone passage. Khellin specifically inspired the development of sodium cromoglycate, a modern anti-asthma drug. Evidence Level: C (preliminary pharmacological and clinical evidence).

Does Khella interact with heart medications or blood thinners?

Khella may interact with anticoagulants, potentially increasing bleeding risk. It can potentiate effects of antihypertensive medications and other calcium channel blockers. Those taking cardiac medications, including antiarrhythmics, should use Khella only under medical supervision due to its effects on heart muscle and rhythm. Evidence Level: C. Always consult a healthcare provider before combining with prescription medications.

What is the recommended dosage of Khella for adults?

Traditional adult dosages range from 300-500mg of standardized extract or approximately 3g of dried herb twice daily. Standardized preparations ensure consistent khellin content for therapeutic effect. Dosage should be individualized under professional guidance, particularly for those with cardiovascular conditions. Evidence Level: Traditional use with limited clinical standardization data.

Is Khella safe to take during pregnancy?

Khella is considered unsafe during pregnancy and breastfeeding. The active compounds khellin and visnagin may stimulate uterine contractions, posing risk of miscarriage or premature labor. These compounds may also pass into breast milk. Pregnant and nursing women should avoid Khella entirely. Evidence Level: C (theoretical concerns based on pharmacological activity).

Can Khella help pass kidney stones naturally?

Traditional use and preliminary evidence suggest Khella may help relax ureteral smooth muscle, potentially facilitating kidney stone passage. The antispasmodic action of khellin reduces ureteral contractions and spasms, which may ease stone movement. Evidence Level: C. However, clinical trials remain limited, and this use requires medical supervision, particularly for larger stones or complications.

Why does Khella cause photosensitivity and how to avoid it?

Khella contains furanocoumarins and khellin, which can cause photosensitivity reactions when skin is exposed to sunlight. This manifests as skin rashes, redness, or hyperpigmentation. Users should avoid direct sun exposure during treatment and use broad-spectrum sunscreen. Evidence Level: C. Photosensitivity typically resolves after discontinuation, but severe reactions require medical attention.

PubMed-compiled information sheet

This sheet was compiled from PubMed (NIH) abstracts using AI assistance. Every factual claim is cited to a real PubMed article (see the source list). It has not yet been human-reviewed — confirm with a healthcare provider before use.

Compiled from 29 PubMed articles · model: gemma4:31b

Summary

Ammi visnaga, also known as Khella, is an annual or biennial herb indigenous to the Mediterranean region used in traditional and modern medicine [PMID:31940874]. It is primarily recognized for its bioactive furanochromones, khellin and visnagin [PMID:34569361].

Background

Ammi visnaga L. (also known as Visnaga daucoides Gaertn. or toothpick weed) is a member of the Apiaceae family found in North Africa, Asia, and Europe [PMID:31940874].

Traditional uses

The plant has been used for centuries as a diuretic and smooth muscle relaxant [PMID:24925412]. It has been used in traditional medicine in Egypt as a remedy for kidney stones [PMID:32189984, PMID:20036111] and in Morocco to treat hypertension [PMID:38115615].

Active compounds

The primary active constituents are the furanochromones khellin and visnagin [PMID:34569361, PMID:33673560]. Other components include essential oils, polyphenolic compounds (flavonoids), phenols, tannins, coumarins, and saponins [PMID:31940874, PMID:38037686].

Mechanism of action

Khellin and visnagin exhibit antilithiogenic and pleiotropic activities [PMID:26692756]. The herb's flavonoid content provides antioxidant activity [PMID:31940874], while its furanochromones can prevent cell damage caused by oxalate in renal epithelial cells [PMID:20036111]. Khellin served as the structural basis for cromolyn sodium, which prevents the release of inflammatory mediators like histamine and leukotrienes from mast cells [PMID:32491405, PMID:24925412].

Clinical evidence

Evidence DUrolithiasis (Kidney Stones)

Ammi visnaga seeds have been used to treat renal colic and kidney stones; in rat models, it highly reduced the incidence of calcium oxalate deposition in kidneys [PMID:31940874, PMID:12452606]. A case report indicated a patient recovered completely from ureteral stones after 10 days of seed use [PMID:26692756].

Evidence DHypertension

Aqueous extract of Ammi visnaga was investigated for antihypertensive activity in rats [PMID:38115615].

Evidence DHypertriglyceridemia

A case report noted that HDL-cholesterol levels returned to normal after 10 days of using A. visnaga seeds [PMID:26692756].

Evidence DSeizures/Neuroinflammation

Fruit hydroalcoholic extract showed neuroprotective, anticonvulsant, and anti-inflammatory properties in a PTZ-induced seizure mouse model [PMID:41182468].

Safety & adverse effects

Ammi visnaga can be highly toxic; a fatal case was reported in an 18-year-old woman who self-medicated with powder for vitiligo, resulting in necrosis of the liver, kidneys, lungs, and pancreas [PMID:41145408]. The estimated toxic dose is 1g per kg [PMID:41145408].

Evidence summary

The evidence is primarily based on preclinical animal models (rats/mice), in vitro studies, and isolated case reports. There is a lack of high-level clinical trial data (RCTs) or systematic reviews for human use.

PubMed sources

1.PMID: 24925412 (2014) — Chromones. · Chemical immunology and allergy
2.PMID: 32491405 (2026) — Mast cell stabilisers. · European journal of pharmacology
3.PMID: 31940874 (2020) — Ammi Visnaga L., a Potential Medicinal Plant: A Review. · Molecules (Basel, Switzerland)
4.PMID: 38797603 (2024) — Therapeutic potential and pharmacological mechanism of visnagin. · Journal of integrative medicine
5.PMID: 37009254 (2023) — Ammi-visnaga extract; a novel phyto-antiviral agent against bovine rotavirus. · Virusdisease
6.PMID: 34569361

Khella Herb

Sources & Citations

Calculate a safe dose of Khella Herb