Drug & supplement interaction

Khella + Guaifenesin

Guaifenesin brand names: Robitussin, Humibid LA, Amibid LA, Numobid, Muco-Fen 800, and others.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 20, 2026
The bottom line No known interaction

We found no known interaction between Khella and Guaifenesin in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first.

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Interaction report

Khella and Guaifenesin

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Guaifenesin and Khella in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Khella safety at a glance

Khella overall Use caution May cause side effects like nausea and sun sensitivity, and quality of evidence is limited.
Pregnancy Likely Unsafe When used orally. The active constituent, khellin, has uterine stimulant activity; contraindicated. Read the full pregnancy detail
Breastfeeding Avoid Not enough safety data; avoid use while breastfeeding.

Pregnancy & breastfeeding ratings are from Natural Medicines (Therapeutic Research Center) — the full detail is in the Special populations card below. Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Guaifenesin and Khella? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Guaifenesin

Interactions in our licensed database are recorded against drug classes, not just single drug names. Guaifenesin is filed under 2 classifications — including oral drugs. Khella has documented interactions with 3 drug classes — the most serious being digoxin (lanoxin) (moderate), hepatotoxic drugs (moderate) and photosensitizing drugs (moderate) — and none of Guaifenesin’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Khella Does Interact With Other Medications

Khella has 618 moderate known drug interactions in our database — Guaifenesin isn’t one of them. If you take anything else, check it against the full list below.

Moderate 618 No known interaction 2,212 (incl. Guaifenesin)
Taking anything else?

Check Another of Your Medications Against Khella

Covers the 2,830 medications we’ve checked against Khella. Pick one to open its full report.

What to actually watch for

What Khella Itself Has Been Linked To

This is not an interaction — nothing below involves Guaifenesin. It is the side-effect record for Khella on its own, from the licensed Natural Medicines monograph. If something new turns up after you add Khella, this list is the first place to look.

  • Sun sensitivity / Itching Additional detail

    “Orally, prolonged use or use of high doses of khella can cause nausea, dizziness, constipation, lack of appetite, headache, itching, and insomnia. In some patients, khella can cause elevated liver transaminase and gamma-glutamyltransferase (GGT) levels (2). There is also some concern that khella might cause photosensitivity (2,7162).”

    Khella · Natural Medicines adverse-effect record, reported in cluster headache.

    2 sources cited
    1. 2. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
    2. 7162. Dr. Duke's Phytochemical and Ethnobotanical Databases. Available at: http://www.ars-grin.gov/duke/.

    “Orally, prolonged use or use of high doses of khella can cause itching (2). There is also some concern that khella might cause photosensitivity because of the constituents khellin and furocoumarin (2,7162).”

    Khella · Natural Medicines adverse-effect record, reported in pruritus.

    2 sources cited
    1. 2. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
    2. 7162. Dr. Duke's Phytochemical and Ethnobotanical Databases. Available at: http://www.ars-grin.gov/duke/.
  • Reduced appetite / Constipation / Nausea Additional detail

    “Orally, prolonged use or use of high doses of khella can cause nausea, constipation, and lack of appetite (2).”

    Khella · Natural Medicines adverse-effect record, reported in constipation.

    1 source cited
    1. 2. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
  • Trouble sleeping / Dizziness / Headache Additional detail

    “Orally, prolonged use or use of high doses of khella can cause dizziness, headache, and insomnia (2).”

    Khella · Natural Medicines adverse-effect record, reported in cluster headache.

    1 source cited
    1. 2. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.

Everything above comes from the Natural Medicines adverse-effect record for Khella — expand a row for the licensed statement it rests on. We haven’t matched Guaifenesin to its FDA label in our system yet, so we can’t compare its own side-effect list here — the leaflet that comes with your prescription is the authoritative list for Guaifenesin.

Special populations

Khella in Pregnancy & Breastfeeding

Pregnancy Likely Unsafe

When used orally. The active constituent, khellin, has uterine stimulant activity; contraindicated.

DISCLAIMER: This tool is intended for informational purposes only, and should not be interpreted as specific medical advice. Patients should consult with a qualified healthcare provider before making decisions about therapies and/or health conditions.© 2026 Therapeutic Research Center

From our Q&A

Questions About Khella or Guaifenesin

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Khella or Guaifenesin, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Guaifenesin

This page covers Khella only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Guaifenesin page lists 26 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), Berberine (moderate), Bitter Orange (moderate) and Coffee Charcoal (moderate).

By severity: 2 major · 15 moderate · 9 minor.

From our pharmacist’s overview on the Guaifenesin page

“Guaifenesin (Robitussin, Humibid LA) loosens chest mucus, and by itself it is a mild medicine, but two of the 26 supplements on this list rate major, so those two deserve your attention first. Activated charcoal can bind the drug in your gut and blunt what it does, and grapefruit raises blood levels of dextromethorphan, the cough suppr…”

Reviewed by 2 · Jul 18, 2026

Open the Guaifenesin interaction page

One more smart check

Taking Khella as Part of a Dietary Supplement Product? Check It for Interactions

We hold 43 real supplement products containing Khella, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Khella. Even though Khella itself has no known interaction with Guaifenesin, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Khella and Guaifenesin Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Khella
Top half

#696 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Guaifenesin
Top half

#1,088 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Khella reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Khella and Guaifenesin records this page draws on were last updated July 11, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Khella

What is Khella?

Khella
  • Asthma and bronchitis
  • Angina and heart-related chest pain
  • Kidney stones
  • Vitiligo and psoriasis
  • Mild high blood pressure

Khella is a Mediterranean herb whose seeds contain compounds like khellin that may relax smooth muscle in the airways and blood vessels. While it has a long history of traditional use for breathing and heart problems, modern evidence in supplement form is limited, and it can cause side effects and sun sensitivity, so talk with your pharmacist or doctor before using it.

Ammi visnaga · Apiaceae · Dried ripe fruit (seeds) · Capsules, tinctures, teas, standardized extracts

An interaction check asks whether these two react with each other — it does not ask whether Khella is a good idea for someone in your situation. Here is what our Khella record says about it on its own.

Khella: dosing

There is no well-established, standardized dose for khella supplements. The right amount depends on the product, how it is prepared, and the amount of active compounds it contains.Because strength varies widely between products, follow the directions on the label and do not exceed them. Avoid long-term use unless guided by a healthcare professional.

From our Khella monograph — the full record covers uses, side effects and every documented interaction.

Read the full Khella monograph & all interactions
Medication

About Guaifenesin

What Is Guaifenesin Used For?

Brand names: Robitussin, Humibid LA, Amibid LA, Numobid, Muco-Fen 800, Bidex, Organidin, X-pect, Mucinex

Guaifenesin helps loosen phlegm (mucus) and thin bronchial secretions — the sticky fluid in your airways — so your cough can clear it out more effectively. It is used to relieve chest congestion associated with colds, respiratory infections, and other conditions that cause a mucus-filled cough.

This use is supported across multiple products including tablets, extended-release tablets, and oral solutions such as Childrens Mucus Relief, Tussin, Guaifenesin STRAWBERRY-BANANA FLAVOR, 12 Hour Mucus Relief, 365 Whole Foods Market Guaifenesin, Dr. Simi Mucus Relief, and others.

See full Guaifenesin drug information
Keep checking

Other Drugs & Khella

Browse every other medication we’ve checked against Khella — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
618Moderate
0Minor
2,211No known interaction
618 Moderate 2,211 No interaction
Moderate

618 interactions

Showing 60 of 618 moderate interactions — see all 618 on the Khella page.

No interaction 2,211 drugs checked — show the list

We also checked Khella against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,211 medications checked with no known interaction — see the full Khella list.

See the full Khella interactions page
See every supplement checked against Guaifenesin, ranked by severity
Evidence & sources

Khella References

The 10 references that drive our Khella monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  1. Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
  2. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  3. Abdel-Fattah A, Aboul-Enein MN, Wassel GM, El-Menshawi BS. An approach to the treatment of vitiligo by khellin. Dermatologica 1982;165:136-40. PubMed
  4. Duarte J, Torres AI, Zarzuelo A. Cardiovascular effects of visnagin on rats. Planta Med 2000;66:35-9. PubMed
  5. Abdel-Fattah A, Aboul-Enein MN, Wassel G, El-Menshawi B. Preliminary report on the therapeutic effect of khellin in psoriasis. Dermatologica 1983;167:109-10. PubMed
  6. Ossenkoppele PM, van der Sluis WG, van Vloten WA. [Phototoxic dermatitis following the use of Ammi majus fruit for vitiligo]. Ned Tijdschr Geneeskd 1991;135:478-80.
  7. Harvengt C, Desager JP. HDL-cholesterol increase in normolipaemic subjects on khellin: a pilot study. Int J Clin Pharmacol Res 1983;3:363-6.
  8. Dr. Duke's Phytochemical and Ethnobotanical Databases. Available at: http://www.ars-grin.gov/duke/.
  9. de Leeuw J, van der BN, Maierhofer G, et al. A case study to evaluate the treatment of vitiligo with khellin encapsulated in L-phenylalanin stabilized phosphatidylcholine liposomes in combination with ultraviolet light therapy. Eur J Dermatol 2003;13(5):
  10. Orecchia G, Perfetti L. Photochemotherapy with topical khellin and sunlight in vitiligo. Dermatology 1992;184(2):120-123. PubMed

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Khella and Guaifenesin Together: Common Questions

Is it safe to take Khella with Guaifenesin?
We do not list a known interaction between Khella and Guaifenesin. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
How was the Khella and Guaifenesin combination checked?
Interactions in our licensed database are recorded against drug classes. Guaifenesin is filed under 2 classifications, and Khella has documented interactions with 3 drug classes — none of Guaifenesin's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Khella interact with any other medications?
Yes. Khella has 618 documented drug interactions in our database — Guaifenesin is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Guaifenesin interact with any supplements?
Yes. Guaifenesin has documented interactions with 26 supplements in our database — Khella is not one of them. The Guaifenesin interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Where next

Keep Exploring

Khella monograph Uses, safety profile, and every drug interaction in one place Guaifenesin drug information The full plain-English guide to this medication Guaifenesin supplement interactions Every supplement checked against Guaifenesin, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 10 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Guaifenesin and Khella?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.