Drug & supplement interaction

Spinach + Valacyclovir

Valacyclovir brand name: Valtrex.

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 Spinach and Valacyclovir 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

Spinach and Valacyclovir

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 Valacyclovir and Spinach 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.

Spinach safety at a glance

Spinach overall Generally safe Spinach is safe and nutritious as a food for most people.
Pregnancy Likely Safe When used in amounts commonly found in foods; avoid medicinal amounts. Read the full pregnancy detail
Breastfeeding Likely Safe When used in amounts commonly found in foods; avoid medicinal amounts. 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 Valacyclovir and Spinach? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Valacyclovir

Interactions in our licensed database are recorded against drug classes, not just single drug names. Valacyclovir is filed under 3 classifications — organic anion transporter 1 (oat1) substrates, seizure threshold lowering drugs, oral drugs. Spinach has documented interactions with 2 drug classes — the most serious being antidiabetes drugs (moderate) and warfarin (coumadin) (moderate) — and none of Valacyclovir’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

Spinach Does Interact With Other Medications

Spinach has 88 moderate known drug interactions in our database — Valacyclovir isn’t one of them. If you take anything else, check it against the full list below.

Moderate 88 No known interaction 2,742 (incl. Valacyclovir)
Taking anything else?

Check Another of Your Medications Against Spinach

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

What to actually watch for

No Interaction Found — But Data Suggests Spinach and Valacyclovir May Share a Side Effect

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.

  • A skin rash Additional detail

    Spinach

    “Topically, contact dermatitis has been reported from spinach in a 54-year-old female farmer.”

    Spinach · Natural Medicines adverse-effect record, reported in dermatitis.

    1 source cited
    1. 41757. Roller, E., Meller, S., Homey, B., Ruzicka, T., and Neumann, N. J. [Contact dermatitis caused by spinach, hedge mustard and chives]. Hautarzt 2003;54(4):374-375.

    Valacyclovir

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

Reported for Spinach but not commonly for Valacyclovir: wheezing.

Effects for Valacyclovir come from the ADVERSE REACTIONS section of its FDA label; effects for Spinach 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

Spinach in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Safe

When used in amounts commonly found in foods; avoid medicinal amounts.

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 Spinach or Valacyclovir

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

This page covers Spinach only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Valacyclovir page lists 27 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), African Wild Potato (moderate), Banderol (moderate), Biofeedback (moderate) and Caffeic Acid (moderate).

By severity: 1 major · 17 moderate · 9 minor.

From our pharmacist’s overview on the Valacyclovir page

“Valacyclovir (Valtrex) works against herpes outbreaks only if enough of it gets absorbed into your blood, and most of this list threatens exactly that. Of the 27 supplements on file, 17 can change how well oral medicines like this one are absorbed, and the single major-rated entry, activated charcoal, binds drugs in the gut outright.”

Reviewed by 2 · Jul 18, 2026

Open the Valacyclovir interaction page

One more smart check

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

We hold 3,925 real supplement products containing Spinach, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Spinach. Even though Spinach itself has no known interaction with Valacyclovir, 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 Spinach and Valacyclovir 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 Spinach
Top 10%

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

29 days ago today
Medication Valacyclovir
Top 5%

#31 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 Spinach reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 20, 2026. The Spinach and Valacyclovir 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 Spinach

What is Spinach?

  • General nutrition and antioxidant support
  • Eye health
  • Heart health and blood pressure
  • Athletic performance
  • Constipation and digestive support

Spinach is a nutrient-dense leafy green that is a healthy part of a balanced diet, providing vitamins, minerals, fiber, and antioxidants. While it is very safe as a food, concentrated supplements and extracts are far less studied, and most specific health claims are not strongly proven. People prone to kidney stones or taking blood thinners should be mindful of its oxalate and vitamin K content.

Spinacia oleracea · Amaranthaceae · Leaves · Fresh or cooked leaves, powders, juice, capsules, and extracts

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

Spinach: dosing

There is no official standardized dose for spinach. As a food, it can be enjoyed in normal serving sizes as part of a balanced diet.For supplements such as powders, capsules, or extracts, a proven dose has not been established. More is not always better, especially given spinach's oxalate and vitamin K content.

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

Read the full Spinach monograph & all interactions
Medication

About Valacyclovir

What Is Valacyclovir Used For?

Brand name: Valtrex

Valacyclovir tablets are used in adults to treat cold sores (herpes labialis), genital herpes (initial and recurrent episodes), and shingles (herpes zoster). They can also be taken daily as suppressive therapy to reduce how often genital herpes outbreaks occur, and to lower the risk of passing genital herpes to a partner.

In children and adolescents, valacyclovir tablets are used to treat cold sores in those aged 12 and older, and chickenpox in those aged 2 to under 18. Valacyclovir has not been established as safe and effective for most uses in immunocompromised patients, with the exception of suppressive therapy for genital herpes in HIV-infected adults.

Most-Reported Side Effects for Valacyclovir

From FAERS, the FDA’s public side-effect reporting system (70,056 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fatigue 4,317 reports
Nausea 3,985 reports
Diarrhea 3,648 reports
Headache 2,964 reports
Fever 2,753 reports
See full Valacyclovir drug information
Keep checking

Other Drugs & Spinach

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

0Major
88Moderate
0Minor
2,741No known interaction
88 Moderate 2,741 No interaction
Moderate

88 interactions

Showing 60 of 88 moderate interactions — see all 88 on the Spinach page.

No interaction 2,741 drugs checked — show the list

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

Showing the 60 most looked-up of 2,741 medications checked with no known interaction — see the full Spinach list.

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

Spinach References

The 6 references that drive our Spinach 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. Karlson, B., Leijd, B., and Hellstrom, K. On the influence of vitamin K-rich vegetables and wine on the effectiveness of warfarin treatment. Acta Med Scand. 1986;220(4):347-350. PubMed
  3. Roller, E., Meller, S., Homey, B., Ruzicka, T., and Neumann, N. J. [Contact dermatitis caused by spinach, hedge mustard and chives]. Hautarzt 2003;54(4):374-375.
  4. Schuller, A., Morisset, M., Maadi, F., Kolopp Sarda, M. N., Fremont, S., Parisot, L., Kanny, G., and Moneret-Vautrin, D. A. Occupational asthma due to allergy to spinach powder in a pasta factory. Allergy 2005;60(3):408-409. PubMed
  5. Gustafsson, K., Asp, N. G., Hagander, B., and Nyman, M. Satiety effects of spinach in mixed meals: comparison with other vegetables. Int.J.Food Sci.Nutr. 1995;46(4):327-334. PubMed
  6. Schreiber, J., Muller, E., Becker, W. M., Zabel, P., Schlaak, M., and Amthor, M. [Spinach powder-induced exogenous allergic alveolitis]. Pneumologie 1998;52(1):61-65.

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 Spinach and Valacyclovir Together: Common Questions

Is it safe to take Spinach with Valacyclovir?
We do not list a known interaction between Spinach and Valacyclovir. 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 Spinach and Valacyclovir have any of the same side effects?
Yes — our sources link each of them separately to one 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 Spinach and Valacyclovir combination checked?
Interactions in our licensed database are recorded against drug classes. Valacyclovir is filed under 3 classifications, and Spinach has documented interactions with 2 drug classes — none of Valacyclovir'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 Spinach interact with any other medications?
Yes. Spinach has 88 documented drug interactions in our database — Valacyclovir 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 Valacyclovir interact with any supplements?
Yes. Valacyclovir has documented interactions with 27 supplements in our database — Spinach is not one of them. The Valacyclovir 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

Spinach monograph Uses, safety profile, and every drug interaction in one place Valacyclovir drug information The full plain-English guide to this medication Valacyclovir supplement interactions Every supplement checked against Valacyclovir, 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 6 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Valacyclovir and Spinach?

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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.