Drug & supplement interaction

Sweet Vernal Grass + Terazosin

Terazosin brand names: Hytrin, Terazosin.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Sweet Vernal Grass and Terazosin 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 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 Terazosin

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

Why No Interaction Is Listed for Terazosin

Interactions in our licensed database are recorded against drug classes, not just single drug names. Terazosin is filed under 3 classifications — alpha-adrenergic antagonists, antihypertensive drugs, oral drugs. Sweet Vernal Grass has documented interactions with 1 drug class — the most serious being anticoagulant/antiplatelet drugs (moderate) — and none of Terazosin’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 — Terazosin 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. Terazosin)
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 Terazosin 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

    Terazosin

    Listed in the ADVERSE REACTIONS section of the FDA label for Terazosin. 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.

    Terazosin

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

  • Sore throat Additional detail

    Sweet Vernal Grass

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

    Terazosin

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

  • Cough / 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.

    Terazosin

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

  • Dizziness / Headache reported in 5.2% of FDA reports for Terazosin 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.

    Terazosin

    Listed in the ADVERSE REACTIONS section of the FDA label for Terazosin, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

  • Itching / 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.

    Terazosin

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

Reported for Sweet Vernal Grass but not commonly for Terazosin: hives.

Effects for Terazosin 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. Where a percentage is shown, it is the share of 8,752 voluntary FDA FAERS reports for Terazosin that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. 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

Everything else you take

See Every Supplement That Interacts With Terazosin

This page covers Sweet Vernal Grass only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Terazosin page lists 137 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), American Hellebore (major), American Mistletoe (major), Tyramine (major) and Adrafinil (moderate).

By severity: 4 major · 112 moderate · 21 minor.

Open the Terazosin interaction page

How much people look this up

Where Sweet Vernal Grass and Terazosin 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
Steady interest

#1,446 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Terazosin
Steady interest

#2,525 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 September 13, 2026. The Sweet Vernal Grass and Terazosin 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 Terazosin

What Is Terazosin Used For?

Brand names: Hytrin, Terazosin

Terazosin capsules and Tezruly oral solution are both used to relieve the urinary symptoms of benign prostatic hyperplasia (BPH) — the enlarged prostate condition that causes trouble urinating — in adult males. They are also used to treat high blood pressure (hypertension), either alone or combined with other blood pressure medicines.

Lowering blood pressure with terazosin reduces the risk of serious cardiovascular events, including strokes and heart attacks. Tezruly (the oral solution) may be used alone or alongside other antihypertensive agents for hypertension.

Most-Reported Side Effects for Terazosin

From FAERS, the FDA’s public side-effect reporting system (8,843 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 543 reports
Dyspnea 502 reports
Diarrhea 458 reports
Dizziness 457 reports
Asthenia 418 reports
See full Terazosin 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 Terazosin, 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 Terazosin Together: Common Questions

Is it safe to take Sweet Vernal Grass with Terazosin?
We do not list a known interaction between Sweet Vernal Grass and Terazosin. 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 Terazosin have any of the same side effects?
Yes — our sources link each of them separately to 9 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.
How was the Sweet Vernal Grass and Terazosin combination checked?
Interactions in our licensed database are recorded against drug classes. Terazosin is filed under 3 classifications, and Sweet Vernal Grass has documented interactions with 1 drug class — none of Terazosin'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 — Terazosin 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 Terazosin interact with any supplements?
Yes. Terazosin has documented interactions with 137 supplements in our database — Sweet Vernal Grass is not one of them. The Terazosin 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 Terazosin drug information The full plain-English guide to this medication Terazosin supplement interactions Every supplement checked against Terazosin, 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 Terazosin 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.