Drug & supplement interaction

Sweet Vernal Grass + Quetiapine

Quetiapine brand names: Seroquel, Dopaquel.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Oct 4, 2026
The bottom line No known interaction

We found no known interaction between Sweet Vernal Grass and Quetiapine 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. Additionally, although there is no interaction, the label for Quetiapine states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Sweet Vernal Grass and Quetiapine

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 Quetiapine and Sweet Vernal Grass 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.

Sweet Vernal Grass safety at a glance

Sweet Vernal Grass overall Use caution Generally used in small amounts as a flavoring, but human safety data as a supplement is very limited and it can trigger allergies.
Pregnancy Possibly Safe When used sublingually as prescribed. An FDA-approved prescription combination product (Oralair) containing sweet vernal grass, orchard grass, perennial rye gra... Read the full pregnancy detail
Breastfeeding Possibly Safe When used sublingually as prescribed. An FDA-approved prescription combination product (Oralair) containing sweet vernal grass, orchard grass, perennial rye gra... Read the full breastfeeding detail

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 Quetiapine and Sweet Vernal Grass? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Quetiapine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Quetiapine is filed under 10 classifications — including antipsychotic drugs, qt interval-prolonging drugs, serotonergic drugs. Sweet Vernal Grass has documented interactions with 1 drug class — the most serious being anticoagulant/antiplatelet drugs (moderate) — and none of Quetiapine’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

Sweet Vernal Grass Does Interact With Other Medications

Sweet Vernal Grass has 122 moderate known drug interactions in our database — Quetiapine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 122 No known interaction 2,708 (incl. Quetiapine)
Taking anything else?

Check Another of Your Medications Against Sweet Vernal Grass

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

What to actually watch for

No Interaction Found — But Data Suggests Sweet Vernal Grass and Quetiapine May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do. 2 of them are worth acting on rather than waiting out — marked below.

  • A severe allergic reaction Worth acting on Additional detail

    Sweet Vernal Grass

    “Sublingually, an FDA-approved combination product (Oralair) containing sweet vernal grass, orchard grass, perennial rye grass, Timothy grass, and Kentucky blue grass pollen extracts can cause pruritus, oral edema, throat irritation, and urticaria. It can also cause severe, life threatening allergic reactions including laryngopharyngeal swelling, angioedema, and anaphylaxis in highly sensitized individuals.”

    Sweet Vernal Grass · Natural Medicines adverse-effect record, reported in pruritus.

    2 sources cited
    1. 97264. Didier A, Bons B. Safety and tolerability of 5-grass pollen tablet sublingual immunotherapy: pooled analysis and clinical review. Expert Opin Drug Saf 2015;14(5):777-88. doi: 10.1517/14740338.2015.1017468. PubMed
    2. 97265. Oralair Product Information. (Sweet vernal, orchard, perennial rye, timothy, and Kentucky blue grass mixed pollens allergen extract). Stallergenes S.A., France. 2014. https://www.fda.gov/downloads/BiologicsBloodVaccines/Allergenics/UCM391580.pdf (accessed

    Quetiapine

    Listed in the ADVERSE REACTIONS section of the FDA label for Quetiapine. Read the label on DailyMed ›

  • An allergic reaction Worth acting on Additional detail

    Sweet Vernal Grass

    “Sublingually, an FDA-approved prescription combination product (Oralair) of sweet vernal grass, orchard grass, perennial rye grass, Timothy grass, and Kentucky blue grass pollen allergen extracts can cause mouth edema and pruritus, throat edema, dyspepsia, and cough. There are also rare reports of severe hypersensitivity reactions.”

    Sweet Vernal Grass · Natural Medicines adverse-effect record, reported in cough.

    2 sources cited
    1. 97264. Didier A, Bons B. Safety and tolerability of 5-grass pollen tablet sublingual immunotherapy: pooled analysis and clinical review. Expert Opin Drug Saf 2015;14(5):777-88. doi: 10.1517/14740338.2015.1017468. PubMed
    2. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

    Quetiapine

    Listed in the ADVERSE REACTIONS section of the FDA label for Quetiapine. Read the label on DailyMed ›

  • Stomach upset Additional detail

    Sweet Vernal Grass

    Recorded for Sweet Vernal Grass in the same Natural Medicines adverse-effect record shown under An allergic reaction above.

    Quetiapine

    Listed in the ADVERSE REACTIONS section of the FDA label for Quetiapine. Read the label on DailyMed ›

  • Swelling Additional detail

    Sweet Vernal Grass

    Recorded for Sweet Vernal Grass in the same Natural Medicines adverse-effect record shown under An allergic reaction above.

    Quetiapine

    Listed in the ADVERSE REACTIONS section of the FDA label for Quetiapine. Read the label on DailyMed ›

  • Dizziness / Headache Additional detail

    Sweet Vernal Grass

    “Orally, use of large doses of sweet vernal grass can cause headaches and dizziness (18).”

    Sweet Vernal Grass · Natural Medicines adverse-effect record, reported in vertigo.

    1 source cited
    1. 18. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

    Quetiapine

    Listed in the ADVERSE REACTIONS section of the FDA label for Quetiapine. Read the label on DailyMed ›

Reported for Sweet Vernal Grass but not commonly for Quetiapine: sore throat, hives, itching and cough.

Effects for Quetiapine come from the ADVERSE REACTIONS section of its FDA label; effects for Sweet Vernal Grass come from the Natural Medicines adverse-effect record, quoted above. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

Special populations

Sweet Vernal Grass in Pregnancy & Breastfeeding

Pregnancy And Lactation Possibly Safe

When used sublingually as prescribed. An FDA-approved prescription combination product (Oralair) containing sweet vernal grass, orchard grass, perennial rye grass, Timothy grass, and Kentucky blue grass pollen extracts has been used sublingually with apparent safety during pregnancy.

Pregnancy And Lactation Likely Unsafe

When dried sweet vernal grass is used orally; avoid using.

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

How to take them

Some Quetiapine Products Have a Food Rule — Sweet Vernal Grass Should Not Break It

At least one FDA label for a product containing Quetiapine says to take it on an empty stomach. Most supplements — Sweet Vernal Grass included — are taken with a meal, so the easy mistake is swallowing both together at breakfast. Where that rule applies, keep Quetiapine on its own and move Sweet Vernal Grass to a meal later in the day.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Quetiapine products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

It is recommended that SEROQUEL XR be taken without food or with a light meal (approximately 300 calories) [see Clinical Pharmacology (12.3) ].

From the Dosage and Administration section of the FDA label we read for Quetiapine — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

From our Q&A

Questions About Sweet Vernal Grass or Quetiapine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Sweet Vernal Grass or Quetiapine, 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 Quetiapine

This page covers Sweet Vernal Grass only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Quetiapine page lists 199 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), Arsenic (major), Cesium (major) and Ephedra (major).

By severity: 11 major · 147 moderate · 41 minor.

From our pharmacist’s overview on the Quetiapine page

“Quetiapine (Seroquel) treats schizophrenia and bipolar disorder, illnesses where an unplanned swing in the drug's blood level has real consequences, and that is why these 199 supplement interactions deserve a careful read rather than a shrug. Most of the risk runs through CYP3A4, the liver enzyme that clears quetiapine: grapefruit bloc…”

Reviewed by 2 · Jul 18, 2026

Open the Quetiapine interaction page

How much people look this up

Where Sweet Vernal Grass and Quetiapine 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 Sweet Vernal Grass
Top 25%

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

29 days ago today
Medication Quetiapine
Top 5%

#72 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 Sweet Vernal Grass reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified October 4, 2026. The Sweet Vernal Grass and Quetiapine records this page draws on were last updated July 10, 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 Sweet Vernal Grass

What is Sweet Vernal Grass?

  • Trouble sleeping
  • Mild anxiety or restlessness
  • Hay fever and allergy symptoms (as a known trigger, sometimes studied)
  • Used as a fragrant flavoring in foods and drinks
  • Folk use for nausea or upset stomach

Sweet Vernal Grass is a fragrant European meadow grass best known for the sweet, hay-like smell it gets from coumarin. It has a long history as a flavoring and a folk calming remedy, but there is very little human research to support any health benefit. It is also a well-known cause of grass-pollen allergies, so people prone to hay fever should be cautious.

Anthoxanthum odoratum · Poaceae · Leaves, flowering tops, and dried grass (whole herb) · Dried herb, tea/infusion, tincture, and as a flavoring/scent component (coumarin source)

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

Sweet Vernal Grass: dosing

There is no established or standardized dose for Sweet Vernal Grass as a supplement. Reliable dosing information from clinical studies does not exist.If you choose to use a product that contains it, follow the directions on the product label and do not exceed the recommended amount.

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

Read the full Sweet Vernal Grass monograph & all interactions
Medication

About Quetiapine

What Is Quetiapine Used For?

Brand names: Seroquel, Dopaquel

Quetiapine treats schizophrenia and bipolar I disorder. This includes manic episodes (and mixed episodes for extended-release products), alone or added to lithium or divalproex. It is also used for depressive episodes of bipolar disorder.

Extended-release quetiapine products (including Seroquel XR) are also approved as add-on therapy with antidepressants for major depressive disorder. The immediate-release tablet labels supplied do not list that use.

See full Quetiapine drug information
Keep checking

Other Drugs & Sweet Vernal Grass

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

0Major
122Moderate
0Minor
2,707No known interaction
122 Moderate 2,707 No interaction
Moderate

122 interactions

Showing 60 of 122 moderate interactions — see all 122 on the Sweet Vernal Grass page.

No interaction 2,707 drugs checked — show the list

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

Showing the 60 most looked-up of 2,707 medications checked with no known interaction — see the full Sweet Vernal Grass list.

See the full Sweet Vernal Grass interactions page
See every supplement checked against Quetiapine, ranked by severity
Evidence & sources

Sweet Vernal Grass References

The 5 references that drive our Sweet Vernal Grass 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. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
  2. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  3. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  4. Didier A, Bons B. Safety and tolerability of 5-grass pollen tablet sublingual immunotherapy: pooled analysis and clinical review. Expert Opin Drug Saf 2015;14(5):777-88. doi: 10.1517/14740338.2015.1017468. PubMed
  5. Oralair Product Information. (Sweet vernal, orchard, perennial rye, timothy, and Kentucky blue grass mixed pollens allergen extract). Stallergenes S.A., France. 2014. https://www.fda.gov/downloads/BiologicsBloodVaccines/Allergenics/UCM391580.pdf (accessed

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 Sweet Vernal Grass and Quetiapine Together: Common Questions

Is it safe to take Sweet Vernal Grass with Quetiapine?
We do not list a known interaction between Sweet Vernal Grass and Quetiapine. 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.
Do Sweet Vernal Grass and Quetiapine have any of the same side effects?
Yes — our sources link each of them separately to 6 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Should I take Sweet Vernal Grass and Quetiapine at the same time of day?
At least one FDA label for a product containing Quetiapine says to take it on an empty stomach, and supplements are usually taken with a meal — so taking them together at breakfast is the easy mistake. Where that applies, keep Quetiapine on its own and move Sweet Vernal Grass to a meal later in the day. Food instructions belong to the product rather than the ingredient, so check the directions on your own box. This is about absorption, not an interaction.
How was the Sweet Vernal Grass and Quetiapine combination checked?
Interactions in our licensed database are recorded against drug classes. Quetiapine is filed under 10 classifications, and Sweet Vernal Grass has documented interactions with 1 drug class — none of Quetiapine'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 Sweet Vernal Grass interact with any other medications?
Yes. Sweet Vernal Grass has 122 documented drug interactions in our database — Quetiapine 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 Quetiapine interact with any supplements?
Yes. Quetiapine has documented interactions with 199 supplements in our database — Sweet Vernal Grass is not one of them. The Quetiapine 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

Sweet Vernal Grass monograph Uses, safety profile, and every drug interaction in one place Quetiapine drug information The full plain-English guide to this medication Quetiapine supplement interactions Every supplement checked against Quetiapine, 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 5 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Quetiapine and Sweet Vernal Grass?

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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.