Drug & supplement interaction

Spanish Broom + Acyclovir

Acyclovir brand names: Zovirax, Zovirax Injection, Sitavig, Avaclyr.

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 Spanish Broom and Acyclovir 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

Spanish Broom and Acyclovir

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 Acyclovir and Spanish Broom 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 Spanish Broom at all — not against Acyclovir, 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.

Spanish Broom safety at a glance

Spanish Broom overall Avoid The plant contains toxic alkaloids and can cause serious poisoning if taken internally.
Pregnancy Avoid Not safe; its alkaloids may affect the uterus and the developing baby.
Breastfeeding Possibly Unsafe When used orally because large amounts of the alkaloid constituent sparteine can stimulate menstrual flow. 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 Acyclovir and Spanish Broom? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

No Interaction Found — But Data Suggests Spanish Broom and Acyclovir 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.

  • Stomach pain / Vomiting Additional detail

    Spanish Broom

    “Information on the adverse effects of Spanish broom is limited. Case reports describe toxicity in adults and children after ingestion of Spanish broom seeds or flowers collected directly from the plant. Symptoms include vomiting, abdominal pain, sedation, headache, dizziness, agitation, and tremors. Adverse effects have not been reported with use of flower extracts in the amounts allowed in foods in the US.”

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

    3 sources cited
    1. 95934. Giménez N, Magro N, Cortés N, Guitart R. Poisoning after Ingestion of Spartium junceum Seeds: Dose-Dependent Effects in Three Boys. J Emerg Med. 2017;53(3):e41-e44. PubMed
    2. 95935. Riccardi A, Frumento F, Ghinatti M, Guiddo G, Lerza R. Spanish Broom flower ingestion: a very unusual poisoning. Eur J Emerg Med. 2006;13(5):317-8. PubMed
    3. 4912. Electronic Code of Federal Regulations. Title 21. Part 182 -- Substances Generally Recognized As Safe. Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=182

    “Ingestion of Spanish broom flowers or seeds collected directly from the plant has been associated with abdominal pain, vomiting, diarrhea, and hypersalivation. In children aged 5-6 years, these symptoms occurred after ingesting 4-8 seeds, with the severity of the effects appearing to be dose-dependent.”

    Spanish Broom · Natural Medicines adverse-effect record, reported in diarrhea.

    2 sources cited
    1. 95934. Giménez N, Magro N, Cortés N, Guitart R. Poisoning after Ingestion of Spartium junceum Seeds: Dose-Dependent Effects in Three Boys. J Emerg Med. 2017;53(3):e41-e44. PubMed
    2. 95935. Riccardi A, Frumento F, Ghinatti M, Guiddo G, Lerza R. Spanish Broom flower ingestion: a very unusual poisoning. Eur J Emerg Med. 2006;13(5):317-8. PubMed

    Acyclovir

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

  • Dizziness / Headache Additional detail

    Spanish Broom

    “Ingestion of Spanish broom flowers or seeds collected directly from the plant has been associated with cases of sedation, confusion, dizziness, headache, agitation, and tremors. In children aged 5-6 years, these symptoms occurred after ingesting 4-8 seeds, with the severity of the effects appearing to be dose-dependent.”

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

    2 sources cited
    1. 95934. Giménez N, Magro N, Cortés N, Guitart R. Poisoning after Ingestion of Spartium junceum Seeds: Dose-Dependent Effects in Three Boys. J Emerg Med. 2017;53(3):e41-e44. PubMed
    2. 95935. Riccardi A, Frumento F, Ghinatti M, Guiddo G, Lerza R. Spanish Broom flower ingestion: a very unusual poisoning. Eur J Emerg Med. 2006;13(5):317-8. PubMed

    Acyclovir

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

Reported for Spanish Broom but not commonly for Acyclovir: confusion, anxiety or restlessness, diarrhea and drowsiness.

Effects for Acyclovir come from the ADVERSE REACTIONS section of its FDA label; effects for Spanish Broom come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 114,761 voluntary FDA FAERS reports for Acyclovir 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

Spanish Broom in Pregnancy & Breastfeeding

Lactation Possibly Unsafe

When used orally because large amounts of the alkaloid constituent sparteine can stimulate menstrual flow.

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 Spanish Broom or Acyclovir

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Spanish Broom or Acyclovir, 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 Acyclovir

This page covers Spanish Broom only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Acyclovir page lists 37 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Asarabacca (major), Siberian Cocklebur (major), African Wild Potato (moderate) and Aristolochia (moderate).

By severity: 3 major · 23 moderate · 11 minor.

From our pharmacist’s overview on the Acyclovir page

“Kidney strain is the risk to understand first. Acyclovir (Zovirax) can stress the kidneys on its own, and a few ingredients here, Siberian cocklebur especially, are toxic to kidney tissue, so pairing them could compound the harm.”

Reviewed by 2 · Jul 18, 2026

Open the Acyclovir interaction page

How much people look this up

Where Spanish Broom and Acyclovir 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 Spanish Broom
Top half

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

29 days ago today
Medication Acyclovir
Top 5%

#59 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 Spanish Broom reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Spanish Broom and Acyclovir 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 Spanish Broom

What is Spanish Broom?

  • Diuretic ('water pill') effect
  • Heart and circulation complaints (folk use)
  • Mild laxative
  • Fragrance in perfumes and cosmetics
  • Traditional fiber and dye source

Spanish Broom is a Mediterranean flowering shrub used historically as a diuretic and heart remedy and today mostly as a perfume ingredient. It contains toxic alkaloids that can affect the heart and nervous system, and there is no reliable modern evidence that it is safe or effective for any health condition. Because of the poisoning risk, it is best avoided as an oral supplement.

Spartium junceum · Fabaceae · Flowers, and sometimes the flowering tops and seeds · Traditional teas or infusions, tinctures, and an essential oil (absolute) used in perfumery; rarely sold as a standardized supplement

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

Spanish Broom: dosing

There is no established safe dose for Spanish Broom as a supplement, and it is not recommended for internal use. Because the plant is toxic and its alkaloid content varies, no reliable, safe amount can be given.We do not provide a dose for this plant.

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

Read the full Spanish Broom monograph & all interactions
Medication

About Acyclovir

What Is Acyclovir Used For?

Brand names: Zovirax, Zovirax Injection, Sitavig, Avaclyr

Acyclovir treats infections caused by herpes viruses. Depending on the form, it is used for cold sores (herpes labialis), genital herpes (initial episodes and recurrent flare-ups), shingles (herpes zoster), and chickenpox (varicella). It can also be used long-term to suppress recurrent genital herpes outbreaks.

Some forms are approved for more serious situations: acyclovir injection is used in hospital settings for herpes simplex encephalitis (herpes infection of the brain), neonatal herpes (in newborns), and herpes or shingles infections in immunocompromised patients. Avaclyr ophthalmic ointment is specifically indicated for acute herpetic keratitis (a herpes ulcer on the cornea of the eye). Sitavig buccal tablet and Zovirax cream are specifically indicated for recurrent cold sores in immunocompetent adults.

Most-Reported Side Effects for Acyclovir

From FAERS, the FDA’s public side-effect reporting system (114,761 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 8,029 reports
Diarrhea 7,348 reports
Pneumonia 5,700 reports
Nausea 5,643 reports
Fever 4,989 reports
See full Acyclovir drug information
Keep checking

Other Drugs & Spanish Broom

Browse every other medication we’ve checked against Spanish Broom — 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 Spanish Broom 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 Spanish Broom list.

See the full Spanish Broom interactions page
See every supplement checked against Acyclovir, ranked by severity
Evidence & sources

Spanish Broom References

The 4 references that drive our Spanish Broom 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. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  2. Electronic Code of Federal Regulations. Title 21. Part 182 -- Substances Generally Recognized As Safe. Available at: https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=182
  3. Giménez N, Magro N, Cortés N, Guitart R. Poisoning after Ingestion of Spartium junceum Seeds: Dose-Dependent Effects in Three Boys. J Emerg Med. 2017;53(3):e41-e44. PubMed
  4. Riccardi A, Frumento F, Ghinatti M, Guiddo G, Lerza R. Spanish Broom flower ingestion: a very unusual poisoning. Eur J Emerg Med. 2006;13(5):317-8. 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 Spanish Broom and Acyclovir Together: Common Questions

Is it safe to take Spanish Broom with Acyclovir?
We do not list a known interaction between Spanish Broom and Acyclovir. 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 Spanish Broom and Acyclovir 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 Acyclovir interact with any supplements?
Yes. Acyclovir has documented interactions with 37 supplements in our database — Spanish Broom is not one of them. The Acyclovir 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

Spanish Broom monograph Uses, safety profile, and every drug interaction in one place Acyclovir drug information The full plain-English guide to this medication Acyclovir supplement interactions Every supplement checked against Acyclovir, 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 4 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Acyclovir and Spanish Broom?

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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.