Asafoetida
Also called asafetida, hing, Ferula assa-foetida, Ferula foetida, asafoetida oleo-gum resin.
Best grade C across 4 graded outcomes Botanical Last checked
The short answer
From 12 sourcesAsafoetida is a pungent plant resin best known as the spice hing. Supplement evidence is thin: two small trials of one resin formulation eased bloating and fullness in functional dyspepsia, and PCOS and COVID-19 studies used other products. Homeopathic asafoetida is a different, highly diluted product, and its IBS trials say nothing about the spice or capsules. Infants have developed dangerous methemoglobinemia after asafoetida folk remedies.
Every graded outcome on this page
4 rows · line = participants- CGrade CFunctional dyspepsia symptoms (early satiety, bloating, heartburn)Indigestionn 62
- CGrade CFunctional dyspepsia symptoms and quality of lifeIndigestionn 43
- DGrade DOvarian follicles and hormones in polycystic ovary syndrome (placebo-controlled)PCOSn 43
- DGrade DMenstrual regularity and pregnancy in polycystic ovary syndromePCOSn 30
Key facts
- US food status
- Asafetida (Ferula assa-foetida and related species) is listed among natural extractives generally recognised as safe for their intended food use6
- Dyspepsia trials
- Two placebo-controlled trials of one formulation (Asafin) improved symptoms: 500 mg/day for 30 days in 43 people and 250 mg/day for 14 days in 62; Cochrane (2023) rated the 2018 trial low-certainty evidence (SMD −1.51)8112
- Drug metabolism
- Four days of asafoetida slowed CYP3A4 and CYP2D6 activity in healthy volunteers (dextromethorphan test)11
- Infant safety
- Two published infant cases of methemoglobinemia after asafoetida remedies, one life-threatening45
- COVID-19 trial
- An asafoetida oleo-gum product (Covexir) reduced cough and other symptoms versus placebo in outpatients with mild to moderate COVID-19; some authors later used the data to seek emergency authorisation for the product in Iran3
What it is
Asafoetida (hing) is the dried oleo-gum resin of Ferula plants, used as a cooking spice and sold in concentrated supplement forms.
How it works
ProposedForms, side by side
2 forms named in our sources. The rest show what our data holds, and say plainly where it holds nothing yet.
Asafoetida forms compared
2 forms| 2 forms | Spice (hing) powder | Standardised oleo-gum resin formulation (capsule) |
|---|---|---|
| Absorption in people | Not studied in the cited trials.6 | Not reported in the trial abstracts.1 |
| GI tolerance | Listed as generally recognised as safe for its intended food use.6 | No adverse events or blood-test changes at 500 mg/day for 30 days; the 2025 trial authors describe it as safe over 14 days at 250 mg/day.81 |
| Studied for | Food flavouring | Functional dyspepsia; COVID-19 symptoms |
- Asafoetida spice (hing) powder
- Standardised oleo-gum resin formulation (capsule)
What the human research says
Human trials only, one row per outcome. The form line shows what each trial actually tested. Grades follow our evidence-grading policy.
Trial map
4 graded outcomes, largest study first4 graded outcomes: 2 improved, 2 mixed. The largest, a 2025 randomized trial of 62 people on functional dyspepsia symptoms (early satiety, bloating, heartburn), found an improvement.
1Functional dyspepsia symptoms (early satiety, bloating, heartburn)
Improved · Grade C · RCT, 62 people, 2025
Adults with functional dyspepsia symptoms
Dose, result and source| Outcome | Found | People | Study | Who was studied |
|---|---|---|---|---|
| Functional dyspepsia symptoms (early satiety, bloating, heartburn) | Improved | 62 | Grade C · RCT, 2025 | Adults with functional dyspepsia symptoms |
| Functional dyspepsia symptoms and quality of life | Improved | 43 | Grade C · RCT, 2018 | People with moderate to severe functional (non-ulcer) dyspepsia in India |
| Ovarian follicles and hormones in polycystic ovary syndrome (placebo-controlled) | Mixed | 43 | Grade D · RCT, 2023 | Young women with polycystic ovary syndrome in Iran (47 enrolled, 43 analysed) |
| Menstrual regularity and pregnancy in polycystic ovary syndrome | Mixed | 30 | Grade D · RCT, 2024 | Women with polycystic ovary syndrome (15 per group) |
Every graded row
4 rowsShowing 4 of 4 outcomes. Human trials only.
CGrade CFunctional dyspepsia symptoms (early satiety, bloating, heartburn)IndigestionLess bloating and early fullnessRCT
n 62 · 2025
Improved Significant time, treatment and treatment × time effects for early satiety, bloating and heartburn (P < .05), with more responders by day 14. Stool form improved, reaction time fell 44% and Bergen Insomnia Scale scores improved (both P < .001).
- Design
- RCT, n = 62, 2025
- Population
- Adults with functional dyspepsia symptoms
- Form
- Food-grade self-emulsifying hydrogel of asafoetida oleo-gum resin (Asafin) vs placebo
- Dose
- 250 mg/day
- Duration
- 14 days
- Source
- Reference 1 · PubMed 41054174 (opens PubMed)
CGrade CFunctional dyspepsia symptoms and quality of lifeIndigestion81% improved vs placeboRCT
n 43 · 2018
Improved About 81% of the asafoetida group improved significantly in overall score and quality of life versus placebo (p < 0.01), and 66% were symptom-free at the end. Symptom scores improved in both groups but more with asafoetida (−5.67 to −25.29 vs −1.55 to −6.0; p ≤ 0.001). No adverse events or blood-test changes occurred.
- Design
- RCT, n = 43, 2018
- Population
- People with moderate to severe functional (non-ulcer) dyspepsia in India
- Form
- Food-grade asafoetida formulation (Asafin) vs placebo
- Dose
- 250 mg twice daily (500 mg/day)
- Duration
- 30 days
- Source
- Reference 8 · PubMed 30224930 (opens PubMed)
DGrade DOvarian follicles and hormones in polycystic ovary syndrome (placebo-controlled)PCOSFewer follicles; clinical signs unchangedRCT
n 43 · 2023
Mixed Ovarian follicle counts fell versus placebo, and DHEAS and TSH levels changed significantly versus placebo (p < 0.03). The full text reports no significant between-group change in clinical measures (BMI, hair growth score, menstruation duration).
- Design
- RCT, n = 43, 2023
- Population
- Young women with polycystic ovary syndrome in Iran (47 enrolled, 43 analysed)
- Form
- Ferula assa-foetida essential oil (root and stem) soft capsules vs fennel oil capsules or placebo
- Dose
- 100 mg twice daily (200 mg/day; from the full text)
- Duration
- 3 months
- Source
- Reference 9 · PubMed 37655000 (opens PubMed)
DGrade DMenstrual regularity and pregnancy in polycystic ovary syndromePCOSMixedRCT
n 30 · 2024
Mixed More pregnancies occurred after asafoetida than after the contraceptive (p = 0.019), and regular cycles lasted longer (p = 0.001). Cycle intervals shortened in both groups; lipids rose only with the contraceptive.
- Design
- RCT, n = 30, 2024
- Population
- Women with polycystic ovary syndrome (15 per group)
- Form
- Asafoetida vs low-dose oral contraceptive (no placebo)
- Dose
- 1 g/day
- Duration
- Two 21-day courses with a 7-day break; follow-up 8 months
- Source
- Reference 2 · PubMed 39086865 (opens PubMed)
What the numbers add up to
Each point is worked out from the data and the sources numbered on this page, with the arithmetic shown under it. It adds no new data and is not medical advice.
One product, two small trials
A contraceptive is the wrong yardstick for fertility
The PCOS trial compared asafoetida with an oral contraceptive, which suppresses ovulation, so more pregnancies in the asafoetida group says little about fertility.2
Studied doses
Doses used in research, shown against the official limits. They describe the studies, not a recommendation for you.
Studied doses in research, not advice. These are amounts used in research, not personal advice. Your clinician or pharmacist can say what fits you.
Doses studied in human trials
Doses studied in human trials ranged from 200 mg/day of a Ferula essential-oil capsule for 3 months (polycystic ovary syndrome) and 250 to 500 mg/day of a resin formulation for 14 to 30 days (functional dyspepsia) to 1 g/day of asafoetida in two 21-day courses (polycystic ovary syndrome). These are research doses, not recommendations.9182
Interactions and safety
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
What Asafoetida meets
2 cited rowsMedicines 2
Supplements and foods 0
No supplement rows in our sources.
- Measured in a human study
- Reference summary
Choose a medicine or supplement above to read its cited rows here.
Also cited:
Drugs broken down by CYP3A4 or CYP2D6
PK studyMeasured in a human study
Drugs broken down by CYP3A4 or CYP2D6, for example cyclosporine, tacrolimus, carbamazepine: In healthy volunteers, 4 days of asafoetida significantly raised the urinary dextromethorphan ratio that tracks CYP3A4 activity and raised the CYP2D6 ratio by 33%, pointing to slower drug breakdown. The authors advise caution with narrow-margin CYP3A4 drugs such as cyclosporine, tacrolimus and carbamazepine.
Source 11, Saudi Pharm J (2014)
Warfarin and other blood thinners
ReviewReference summary
Warfarin and other blood thinners, for example warfarin: A 2000 pharmacy review lists asafoetida among herbs that may raise bleeding risk or add to warfarin's effect. It notes that nearly all herb-warfarin information comes from lab, animal or single case data.
Source 7, Am J Health Syst Pharm (2000)
Interactions
2 agents| Agent | What the source says | Evidence |
|---|---|---|
| Medicines2 | ||
| Warfarin and other blood thinnerse.g. warfarin | A 2000 pharmacy review lists asafoetida among herbs that may raise bleeding risk or add to warfarin's effect. It notes that nearly all herb-warfarin information comes from lab, animal or single case data.7 | Review |
| Drugs broken down by CYP3A4 or CYP2D6e.g. cyclosporine, tacrolimus, carbamazepine | In healthy volunteers, 4 days of asafoetida significantly raised the urinary dextromethorphan ratio that tracks CYP3A4 activity and raised the CYP2D6 ratio by 33%, pointing to slower drug breakdown. The authors advise caution with narrow-margin CYP3A4 drugs such as cyclosporine, tacrolimus and carbamazepine.11 | PK study |
Check with what you take
Kept on this device onlyAdd what you take. We list every interaction our evidence profiles cite between Asafoetida and your picks, and between your picks.
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Add a supplement or medicine you take to check it against Asafoetida.
Starting from one medicine? The interaction checker rates how serious each pair is, on a curated list of 19 entries for 11 medicines. This cabinet has no severity rating: it lists every interaction row our supplement pages cite.
Who should be careful
4 groups- Infants and young children
- Infants have developed methemoglobinemia, an oxygen-carrying blood disorder, after asafoetida remedies; one 2019 case was life-threatening and the authors advise avoiding asafoetida remedies in infants.45
- Pregnancy and breastfeeding
- The cited trials give no safety data in pregnancy or breastfeeding; pregnancies in the PCOS trial occurred after the courses ended.12
- People with serious or persistent digestive symptoms
- The only supplement trial lasted 14 days in functional dyspepsia; it does not address other causes of indigestion.1
- Transplant, seizure and other narrow-margin medicines
- A volunteer study found asafoetida slowed CYP3A4 and CYP2D6 drug metabolism; the authors advise caution with drugs such as cyclosporine, tacrolimus and carbamazepine.11
Methemoglobinemia in infants
2 notesHow to read the label
What to check on the Supplement Facts panel.
How to read the label
2 checksSpice vs supplement
Frequently asked questions
Short answers to common questions; the numbers link to the sources below.
Common questions
7 answersDoes asafoetida help bloating or indigestion?
Can asafoetida improve fertility or cycles in PCOS?
What are the side effects of asafoetida?
Is asafoetida safe for babies?
Is hing safe in cooking?
Asafetida is listed by the FDA as generally recognised as safe for its intended food use as a flavouring.6
Is homeopathic asafoetida the same as asafoetida capsules?
No. Homeopathic remedies are highly diluted preparations, a different product from the spice or resin capsules, so their results do not apply to them. A 2019 Cochrane review found two small trials of homeopathic asafoetida in IBS with constipation, rated very low-certainty evidence, and drew no firm conclusions.10
Was it tested for COVID-19?
An asafoetida product (Covexir) reduced cough and some other symptoms versus placebo in outpatients with mild to moderate COVID-19. It is a single trial, and some authors used the data to seek emergency authorisation for the product in Iran.3
Sources
12 sources: trial abstracts, NIH fact sheets and reference databases. Numbers in the text link here.
Sources cited on this page
12 sources- 1Ferula asafoetida oleo-gum resin alleviates dyspepsia symptoms through modulation of microbiome-gut-brain axis: A randomized, double-blind, placebo-controlled study.RCT Medicine (Baltimore), 2025 · PMID 41054174
- 2A preliminary report comparing the effect of Asafoetida with oral contraceptive on polycystic ovarian syndrome in a double-blind randomized trial.RCT Avicenna J Phytomed, 2024 · PMID 39086865
- 3Efficacy of Covexir® (Ferula foetida oleo-gum) treatment in symptomatic improvement of patients with mild to moderate COVID-19: A randomized, double-blind, placebo-controlled trial.RCT Phytother Res, 2022 · PMID 35896167
- 4Methemoglobinemia in an infant treated with the folk remedy glycerited asafoetida.Observational Pediatrics, 1984 · PMID 6609339
- 5Severe Methemoglobinemia Secondary to Ferula asafoetida Ingestion in an Infant: A Case Report.Observational Saudi J Med Med Sci, 2020 · PMID 31929780
- 621 CFR 182.20 Essential oils, oleoresins (solvent-free), and natural extractives (including distillates) generally recognized as safeGuideline US Food and Drug Administration (eCFR), 1985 · ecfr.gov
- 7Potential interactions between alternative therapies and warfarin.Review Am J Health Syst Pharm, 2000 · PMID 10902065
- 8Safety and Efficacy of Ferula asafoetida in Functional Dyspepsia: A Randomized, Double-Blinded, Placebo-Controlled Study.RCT Evid Based Complement Alternat Med, 2018 · PMID 30224930
- 9"Ferula assa-foetida L" or "Foeniculum vulgare"? Which one is more effective in the management of polycystic ovarian syndrome? A randomized, placebo controlled, triple-blinded.RCT Avicenna J Phytomed, 2023 · PMID 37655000
- 10Homeopathy for treatment of irritable bowel syndrome.Systematic review Cochrane Database Syst Rev, 2019 · PMID 31483486
- 11Modulation of CYP2D6 and CYP3A4 metabolic activities by Ferula asafetida resin.PK study Saudi Pharm J, 2014 · PMID 25561870
- 12Non-Chinese herbal medicines for functional dyspepsia.Systematic review Cochrane Database Syst Rev, 2023 · PMID 37323050
What changed
Every dated change to this page: what changed, who made it and why.
Change log
4 entries| Date | Change | Who and why |
|---|---|---|
| evidence, interactions, safety, FAQ, questions | Added graded rows for the 2018 dyspepsia trial of the same Asafin formulation (43 people, 30 days), and a 2023 placebo-controlled PCOS trial of a Ferula essential oil; noted the 2023 Cochrane rating of the dyspepsia evidence. Fact-check: the 2019 Cochrane review of homeopathic asafoetida in IBS (2 trials, very low certainty) is in an FAQ answer only, not a graded row, because homeopathic dilutions are not evidence for the resin or spice. Added a CYP3A4/CYP2D6 interaction from a 2014 volunteer study, with a matching safety note. Updated summary, studied doses, key facts, label guide, the forms tolerance line and the insight; replaced the FAQ item that repeated the auto-derived "What is" question with a side-effects answer and reworded the PCOS question; added a page question and the gut goal-hub link. Not added: the 2022 Covexir COVID-19 trial reports no participant count in its abstract or the PMC copy, and the 2024 Phytopaj COVID-19 trial tested a blend without between-group statistics in its abstract. LiverTox and LactMed have no asafoetida entry. | Writer: Kymata Health EditorialTrigger: A–Z audit against docs/supplements/AUDIT-STANDARD.md |
| Interactions | Added 1 interaction entry (Warfarin and other blood thinners) from peer-reviewed reviews; each PubMed abstract or full text was read for the cited statement. | Writer: Kymata Health EditorialTrigger: Update |
| all | Independent adversarial review: relabelled the dyspepsia-trial disclosure as maker ties (the abstract shows author affiliations, not funding) and added the COVID-19 trial's disclosed conflict of interest. | Writer: Kymata Health EditorialTrigger: review |
| all | Initial editorial evidence review (first draft). Every PMID checked against NCBI E-utilities esummary (titles and years taken from the record, none retracted) and the abstract read for each cited row. Studied doses are reported as research doses, not dosing advice. | Writer: Kymata Health EditorialTrigger: new page |
Supplement & Nutrient Encyclopedia. Educational information only; it is not medical advice and does not replace a clinician. Dietary supplements are not intended to diagnose, treat, cure or prevent any disease. Statements about supplements have not been evaluated by the FDA.