Drug & supplement interaction

Fool's Parsley + Leucovorin Calcium

Leucovorin Calcium brand name: Wellcovorin.

No Known Interaction
The bottom line No known interaction

We found no known interaction between Fool's Parsley and Leucovorin Calcium 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.

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Interaction report

Fool's Parsley and Leucovorin Calcium

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 Leucovorin Calcium and Fool's Parsley 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 Fool's Parsley at all — not against Leucovorin Calcium, 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.

Fool's Parsley safety at a glance

Fool's Parsley overall Avoid The raw plant is toxic and easily confused with edible parsley, so it should not be consumed.
Pregnancy Likely Unsafe When used orally due to potential for poisoning. Read the full pregnancy detail
Breastfeeding Likely Unsafe When used orally due to potential for poisoning. 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 Leucovorin Calcium and Fool's Parsley? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
What to actually watch for

What Leucovorin Calcium’s Own FDA Label Lists

This is not an interaction — none of it involves Fool's Parsley. These are the most notable effects listed in the ADVERSE REACTIONS section of Leucovorin Calcium’s own FDA label, for the medication by itself. Knowing the drug’s own list makes it easier to work out the likely cause if something new turns up while you take both. 5 of them are worth acting on rather than waiting out — marked below.

  • A low white blood cell count Worth acting on mentioned in 5.8% of FDA reports for Leucovorin Calcium
  • A low platelet count Worth acting on
  • Kidney problems Worth acting on
  • Hives Worth acting on
  • A higher chance of infection Worth acting on
  • Mouth irritation or sores
  • Hair loss
  • Reduced appetite
  • Constipation
  • Diarrhea mentioned in 9.5% of FDA reports for Leucovorin Calcium

Showing the 10 most notable of 14 label-listed effects — ranked by how unusual each one is across medicines generally, with serious effects weighted up.

From the ADVERSE REACTIONS section of the FDA label for Leucovorin Calcium. Read the label on DailyMed › Where a percentage is shown, it is the share of 19,003 voluntary FDA FAERS reports for Leucovorin Calcium that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Fool's Parsley’s licensed record lists no adverse effects our clinical vocabulary could match, so there is no Fool's Parsley side to compare — that is a limit of the record, not a statement that Fool's Parsley has no side effects.

Special populations

Fool's Parsley in Pregnancy & Breastfeeding

Pregnancy And Lactation Likely Unsafe

When used orally due to potential for poisoning.

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 Leucovorin Calcium

This page covers Fool's Parsley only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Leucovorin Calcium page lists 17 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Coffee Charcoal (moderate), European Mandrake (moderate), Glucomannan (moderate) and Guar Gum (moderate).

By severity: 1 major · 7 moderate · 9 minor.

Open the Leucovorin Calcium interaction page

How much people look this up

Where Fool's Parsley and Leucovorin Calcium 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 Fool's Parsley
Steady interest

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

29 days ago today
Medication Leucovorin Calcium
Top 25%

#537 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 Fool's Parsley reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Fool's Parsley and Leucovorin Calcium records this page draws on were last updated June 22, 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 Fool's Parsley

What is Fool's Parsley?

  • Digestive complaints (traditional/homeopathic)
  • Diarrhea in children (homeopathic tradition)
  • Nausea and vomiting (homeopathic tradition)
  • Restlessness (homeopathic tradition)

Fool's Parsley is a poisonous weed that closely resembles edible parsley and has no proven medicinal benefit. The raw plant is toxic and should never be eaten; the only modern use is in highly diluted homeopathic products, which lack reliable evidence of effectiveness. If you are looking for a culinary herb, do not gather wild plants that resemble parsley.

Aethusa cynapium · Apiaceae · Whole plant (aerial parts), occasionally used in homeopathic preparations · Homeopathic dilutions; rarely as crude plant material (not recommended)

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

Fool's Parsley: dosing

There is no established safe medicinal dose of Fool's Parsley. The crude plant is poisonous and should not be taken at any amount.For homeopathic products, dosing follows the directions on the specific product label, but these are not standardized medical doses and are not supported by strong evidence.

From our Fool's Parsley monograph — the full record covers uses, side effects and every documented interaction.

Read the full Fool's Parsley monograph & all interactions
Medication

About Leucovorin

What Is Leucovorin Used For?

Brand name: Wellcovorin

Leucovorin is used to reduce the harmful effects of methotrexate when the body is slow to clear it, and to counteract accidental overdoses of drugs that block folic acid (called folic acid antagonists or DHFR inhibitors). It is also used to treat cerebral folate transport deficiency (FOLR1-CFTD), a rare genetic condition that prevents the brain from receiving enough folate.

The injectable forms — including leucovorin calcium injection and Vykoura — are additionally approved for rescue after high-dose methotrexate therapy, for treatment of megaloblastic anemia (a type of anemia caused by low folic acid) when oral treatment isn't possible, and for use alongside fluorouracil in treating metastatic colorectal cancer. Leucovorin calcium injection is specifically indicated for rescue after high-dose methotrexate in osteosarcoma.

Most-Reported Side Effects for Leucovorin Calcium

From FAERS, the FDA’s public side-effect reporting system (19,003 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Diarrhea 1,799 reports
Nausea 1,388 reports
Vomiting 1,135 reports
Neutropenia 1,094 reports
Fever 1,011 reports
See full Leucovorin drug information
Keep checking

Other Drugs & Fool's Parsley

Browse every other medication we’ve checked against Fool's Parsley — 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
No interaction 2,829 drugs checked — show the list
Evidence & sources

Fool's Parsley References

The 1 references that drive our Fool's Parsley 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. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.

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 Fool's Parsley and Leucovorin Calcium Together: Common Questions

Is it safe to take Fool's Parsley with Leucovorin Calcium?
We do not list a known interaction between Fool's Parsley and Leucovorin Calcium. 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.
Does Leucovorin Calcium interact with any supplements?
Yes. Leucovorin Calcium has documented interactions with 17 supplements in our database — Fool's Parsley is not one of them. The Leucovorin Calcium interaction page linked on this page lists every one, ranked by severity.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Still Have a Question About Leucovorin Calcium and Fool's Parsley?

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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.