Drug & supplement interaction

Ostrich Fern + Riociguat

Riociguat brand name: Adempas.

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 Ostrich Fern and Riociguat 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

Ostrich Fern and Riociguat

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 Riociguat and Ostrich Fern 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.

Worth understanding: our licensed dataset holds no drug-interaction record for Ostrich Fern at all — not against Riociguat, and not against any other medication we track. This verdict therefore rests on the absence of any recorded data, not on research that looked at this combination and found nothing. We cannot rule an interaction out.

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.

Ostrich Fern safety at a glance

Ostrich Fern overall Use caution Generally treated as a food, but raw or undercooked fiddleheads can cause foodborne illness.
Pregnancy Avoid Not enough safety information; avoid medicinal use and never eat them raw or undercooked.
Breastfeeding Use caution Little safety data; well-cooked fiddleheads eaten as food are likely fine, but avoid concentrated or medicinal use.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Riociguat and Ostrich Fern? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Ostrich Fern and Riociguat 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.

  • Diarrhea / Headache / Nausea / Vomiting reported in 13.9% of FDA reports for Riociguat Additional detail

    Ostrich Fern

    “Orally, no adverse effects have been reported when ostrich fern is used medicinally. However, a thorough evaluation of safety outcomes has not been conducted. Eating the young shoots of ostrich fern without proper cooking can cause nausea, vomiting, abdominal cramping (6), diarrhea, and headaches.”

    Ostrich Fern · Natural Medicines adverse-effect record, reported in diarrhea.

    2 sources cited
    1. 6. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
    2. 5002. Centers for Disease Control and Prev. Ostrich fern poisoning New York and western Canada, 1994. JAMA 1995;273:912-3.

    “When consumed as food, the young shoots of ostrich fern (fiddleheads) must be cooked thoroughly (e.g., boiling for 10 minutes) before eating. The Centers for Disease Control and Prevention (CDC) links outbreaks of severe food poisoning to consumption of raw or lightly cooked ostrich ferns (6,5002). Ostrich fern can cause nausea, vomiting, abdominal cramping (6), diarrhea, and headaches after ingestion.”

    Ostrich Fern · Natural Medicines adverse-effect record, reported in diarrhea.

    2 sources cited
    1. 5002. Centers for Disease Control and Prev. Ostrich fern poisoning New York and western Canada, 1994. JAMA 1995;273:912-3.
    2. 6. The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.

    Riociguat

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

Reported for Ostrich Fern but not commonly for Riociguat: stomach pain.

Effects for Riociguat come from the ADVERSE REACTIONS section of its FDA label; effects for Ostrich Fern come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 32,415 voluntary FDA FAERS reports for Riociguat 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.

Everything else you take

See Every Supplement That Interacts With Riociguat

This page covers Ostrich Fern only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Riociguat page lists 230 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), Grapefruit (major) and St. John's Wort (major).

By severity: 6 major · 187 moderate · 37 minor.

From our pharmacist’s overview on the Riociguat page

“Riociguat (Adempas) works by relaxing the blood vessels in your lungs, which also lowers blood pressure, so I read this list of 230 supplements and herbs with real concern, and the six rated major are what to understand first. Grapefruit can push riociguat levels up and intensify its effect, while St.”

Reviewed by 2 · Jul 18, 2026

Open the Riociguat interaction page

How much people look this up

Where Ostrich Fern and Riociguat 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 Ostrich Fern
Steady interest

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

29 days ago today
Medication Riociguat
Steady interest

#2,504 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 Ostrich Fern reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified October 4, 2026. The Ostrich Fern and Riociguat 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 Ostrich Fern

What is Ostrich Fern?

  • Seasonal food/vegetable
  • Source of vitamins and antioxidants
  • Traditional spring tonic
  • Digestive support (traditional)

Ostrich fern is best known as a foraged spring vegetable called a fiddlehead, not as a medicinal supplement. There is very little scientific evidence supporting any health benefit, and raw or undercooked fiddleheads can cause food poisoning, so they must always be thoroughly cooked.

Matteuccia struthiopteris · Onocleaceae · Young curled shoots (fiddleheads) · Fresh or frozen fiddleheads (cooked as a vegetable); rarely as a foraged food

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

Ostrich Fern: dosing

There is no established medicinal dose for ostrich fern, and it is not sold as a standardized supplement. When preparing fiddleheads at home, focus on thorough cooking rather than any particular "dose."

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

Read the full Ostrich Fern monograph & all interactions
Medication

About Riociguat

What Is Riociguat Used For?

Brand name: Adempas

Riociguat — sold as Adempas and under the generic name Riociguat — is used to treat adults with two conditions that cause dangerously high blood pressure in the arteries of the lungs.

  • Chronic Thromboembolic Pulmonary Hypertension (CTEPH): Used after surgical treatment, or when surgery is not an option, to improve exercise capacity and functional class.
  • Pulmonary Arterial Hypertension (PAH): Used to improve exercise capacity, functional class, and to delay the condition from getting worse. It can be used alone or combined with certain other PAH medicines.

Most-Reported Side Effects for Riociguat

From FAERS, the FDA’s public side-effect reporting system (32,415 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Dyspnea 5,718 reports
Headache 4,513 reports
Nausea 3,769 reports
Diarrhea 3,533 reports
Dizziness 3,522 reports
See full Riociguat drug information
Keep checking

Other Drugs & Ostrich Fern

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

0Major
0Moderate
0Minor
2,829No known interaction
2,829 No interaction
No interaction 2,829 drugs checked — show the list

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

Showing the 60 most looked-up of 2,829 medications checked with no known interaction — see the full Ostrich Fern list.

See the full Ostrich Fern interactions page
See every supplement checked against Riociguat, ranked by severity
Evidence & sources

Ostrich Fern References

The 2 references that drive our Ostrich Fern 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. Centers for Disease Control and Prev. Ostrich fern poisoning New York and western Canada, 1994. JAMA 1995;273:912-3.

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 Ostrich Fern and Riociguat Together: Common Questions

Is it safe to take Ostrich Fern with Riociguat?
We do not list a known interaction between Ostrich Fern and Riociguat. 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 Ostrich Fern and Riociguat have any of the same side effects?
Yes — our sources link each of them separately to 4 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.
Does Riociguat interact with any supplements?
Yes. Riociguat has documented interactions with 230 supplements in our database — Ostrich Fern is not one of them. The Riociguat 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

Ostrich Fern monograph Uses, safety profile, and every drug interaction in one place Riociguat drug information The full plain-English guide to this medication Riociguat supplement interactions Every supplement checked against Riociguat, 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 2 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Riociguat and Ostrich Fern?

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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.