Parsley (Petroselinum crispum)

Parsley (Petroselinum crispum) is the familiar bright-green Mediterranean culinary herb used as a garnish, a salad ingredient (tabbouleh), and a finishing herb across European, Middle Eastern, and North African cooking. At normal culinary doses — chopped into salads, sauces, and stews — parsley is a vitamin K-rich, vitamin C-bearing food contributing to a varied diet. Camden uses parsley leaf as a small supporting active in NB-553 (Vitamin C Acerola gummy) where the authorised UK vitamin C health claims attach to the combined vitamin C content rather than to the parsley itself. Three practical things to know: 1. <strong>Parsley leaf at food and supplement doses is not parsley essential oil.</strong> The leaf is a normal food. Concentrated parsley essential oil (high apiole + myristicin) has historical use as a high-dose emmenagogue and has caused fatalities at overdose levels. Food-supplement-tier parsley powder is not the essential oil. 2. <strong>Parsley is a vitamin K-rich food.</strong> If you take warfarin, your dietitian and anticoagulation clinic want a stable weekly vitamin K intake — sudden large increases or decreases in parsley (or any green leafy intake) can affect INR. Talk to your anticoagulation clinic before changing intake significantly. 3. <strong>Pregnancy: culinary intake fine, supplement-extract caution.</strong> Eating parsley as a food during pregnancy is not a concern. High-dose parsley extract supplements are best avoided in pregnancy, and parsley essential oil is contraindicated in pregnancy. Talk to your midwife or pharmacist before starting any new supplement during pregnancy.

Camden Medicals editorial · Last reviewed 12 May 2026 · Next review November 2026

  • Cross-checked against
  • NHS
  • NICE
  • BNF
  • EFSA
  • FSA
Verifera Evidence ReviewCamden evidence review · independently appraised — graded, not guessed.

Camden's editorial team independently graded each health claim below on the strength of the published evidence — see the grade beside every condition.

Class
Botanical
Typical daily dose
Culinary doses (small handful of fresh chopped parsley) are not associated with measurable supplement-class clinical effects. Food-supplement parsley leaf powders are typically 200–500 mg per portion; clinical trial doses vary and have not converged on a standard dose for any outcome.
Top use evidence
Strong
On this page
  1. What it is
  2. How it works

What it is

Parsley (Petroselinum crispum) is a biennial herb in the Apiaceae family (the carrot / celery / fennel / cumin family), native to the central Mediterranean and now cultivated globally as a culinary herb. The two main varieties are curly-leaf parsley (Petroselinum crispum var. crispum) and flat-leaf (Italian) parsley (var. neapolitanum); flat-leaf is generally preferred for cooking, curly for garnish. The cultivated root variety (Hamburg parsley, var. tuberosum) is a separate vegetable.

Parsley leaf is sold as a fresh culinary herb, a dried culinary spice, a freeze-dried powder for supplements, and as a tea. Concentrated parsley essential oil (high apiole + myristicin) is a separate product class — it is NOT a food supplement, is not sold over the counter as a food, and has historical illegal use as a high-dose abortifacient with documented fatalities. The Camden encyclopaedia entry covers only the food / food- supplement-tier leaf product.

At a glance

  • A bright-green Mediterranean culinary herb (Petroselinum crispum) — a food first, a supplement second.
  • No UK-authorised health claims for parsley itself; vitamin C and vitamin K claims attach to the combined nutrient content of a product.
  • Vitamin K-rich — relevant if you take warfarin. Talk to your anticoagulation clinic before changing intake significantly.
  • Pregnancy: culinary intake fine. High-dose extract supplements + parsley essential oil are best avoided — talk to your midwife.
  • Parsley leaf (food / food-supplement) is NOT parsley essential oil. Different regulatory tier, different safety profile.

What people use it for

  • People including fresh parsley in their normal diet (tabbouleh, garnish, salads)

    Parsley is a food. It contributes vitamin K, vitamin C, and a varied phytochemical intake. No specific health claim is authorised on parsley itself.

    Popular, not provenInsufficient

  • Adults seeking small additional botanical vitamin C and vitamin K intake

    Parsley contributes to vitamin C and vitamin K content of a product. The authorised UK vitamin C and K claims attach to per-portion nutrient levels (≥15% NRV) regardless of botanical source. [5]

    Some evidenceStrong

  • People taking warfarin or other vitamin K antagonists

    Consistency of dietary vitamin K intake matters more than absolute level. Talk to your anticoagulation clinic before substantially changing your green-leafy-herb intake (parsley, kale, spinach, broccoli). A small amount of parsley in food is rarely a concern; a daily concentrated parsley supplement is worth discussing. [1]

    Some evidenceStrong

  • Adults seeking traditional diuretic / urinary-tract framing

    Parsley has a long traditional use as a mild diuretic and in folk preparations for urinary complaints. Clinical evidence for diuretic effect at food doses is weak; persistent urinary symptoms need GP review (urinary tract infection, prostate, kidney pathways), not a supplement. [6]

    Some evidenceLimited

How it works

Parsley contributes vitamins and phytochemicals from its leaf matrix. The major nutritional contributions are vitamin K1 (phylloquinone) — fresh parsley is among the highest natural sources of vitamin K1 in the European diet — and vitamin C. Flavonoids (apigenin, luteolin) and the phenylpropanoid apiole are characteristic phytochemicals. At culinary and food- supplement doses these contribute to a varied diet without delivering clinical-trial doses of any single compound.

The vitamin K1 content has direct relevance to warfarin therapy: warfarin is a vitamin K antagonist, and large changes in dietary vitamin K intake — including from green leafy herbs like parsley — can move the INR. The clinical guidance is consistency, not avoidance; your anticoagulation clinic will calibrate the warfarin dose to your habitual diet. Sudden large increases or decreases in parsley, kale, spinach, or other vitamin K-rich foods need a conversation with your clinic.

Common myths

Myth"Parsley essential oil is just stronger parsley leaf"

RealityIt is a different product class. Parsley essential oil is a distilled concentrate of apiole and myristicin at levels far higher than the whole leaf. It is not sold as a food in the UK. Historical high-dose use as an abortifacient has produced fatalities. Parsley leaf (food / food-supplement) is NOT the essential oil.

Myth"Parsley cleanses your kidneys"

RealityIt does not. Your kidneys do not need cleansing by herbs; they are doing their job continuously, and botanical "cleanse" or "purification" claims are not authorised in the UK. If you have a kidney concern, the NHS pathway (urine dip, blood tests, GP review) is what you need. [4]

Myth"Parsley reverses bad breath / hangovers / etc."

RealityChewing fresh parsley does provide some immediate breath freshening from chlorophyll content — a real but small and very short-lived effect. Claims about hangovers, "alkalising" the body, or curing systemic conditions are not supported by clinical evidence and are not authorised in the UK.

Common online questions

Synthesised from the questions UK shoppers most often ask online about Parsley (Petroselinum crispum). Each answer is editorial and links to its evidence in the Sources list below.

Can I take parsley supplements with warfarin?

Talk to your anticoagulation clinic first. Parsley is a high source of vitamin K1, and warfarin is a vitamin K antagonist. The clinical guidance is consistency: keep your weekly green- leafy-herb intake reasonably stable so your INR is predictable. A daily concentrated parsley supplement counts as a real change in intake and should be discussed with your clinic before starting. [1]

Is parsley safe in pregnancy?

Eating parsley as a food (chopped in tabbouleh, garnish on cooked dishes, fresh herb in salads) is fine and is part of many cuisines during pregnancy. The caution is for concentrated parsley-extract supplements at high doses and for parsley essential oil — parsley essential oil contains apiole and myristicin at concentrated levels and is contraindicated in pregnancy. Food-supplement-tier parsley leaf is not the essential oil, but if you are pregnant, talk to your midwife or pharmacist before starting any new supplement. [2]

Is parsley a natural diuretic?

Traditional use suggests so, and parsley tea has been used across European folk medicine for "water retention" and urinary complaints. Clinical evidence for a meaningful diuretic effect at food-supplement doses is weak. If you have ankle or leg swelling, frequent urination, or other urinary symptoms, these can have important causes (heart, kidney, urinary infection) and need GP review rather than a self- managed supplement. [6]

🔬 Camden’s evidence review

The research Camden reviewed, graded on its strength. This is our own appraisal — it sits beneath the official guidance above, never above it.

  1. Vitamin C and vitamin K status

    StrongEvidencestrong

    Parsley leaf is a well-characterised dietary source of vitamin C and (especially) vitamin K1. The authorised UK vitamin C and vitamin K health claims become available to a product when its nutrient content reaches the 15% NRV threshold per labelled portion, regardless of botanical source. [5]

  2. Diuretic / urinary tract

    LimitedEvidencelimited

    Traditional use as a diuretic and for urinary complaints is long-standing across European folk medicine. Modern clinical evidence at food-supplement doses is weak. Symptoms of urinary tract infection (burning, frequency, urgency, fever) need NHS review for diagnosis and treatment. [6]

  3. Blood-glucose / cardiometabolic markers

    LimitedEvidencelimited

    Some small trials of parsley-leaf preparations have reported minor changes in glucose or lipid markers. Sample sizes are small and clinical relevance is unclear. Parsley is not a treatment for diabetes or cardiometabolic disease. [7]

Safety

Parsley as a food is fine. As a supplement at typical doses it is well-tolerated. Talk to your anticoagulation clinic before substantial intake changes if you take warfarin. Avoid concentrated parsley supplements + essential oil in pregnancy.

Talk to your pharmacist or GP first if you:

  • You take warfarin or other vitamin K antagonists — vitamin K consistency matters.
  • You take antiplatelets or DOACs (apixaban, rivaroxaban, dabigatran, edoxaban) — less direct vitamin K interaction, but disclose all supplements.
  • You take prescribed diuretics — additive effect at high parsley intake is theoretical but discuss.
  • You have diagnosed kidney disease — high oxalate / mineral intake from concentrated herb products warrants discussion.
  • You are pregnant, trying to conceive, or breastfeeding — talk to your midwife or pharmacist before any new supplement.

Common side effects: Generally well-tolerated at food and food-supplement doses. Rare photosensitivity at very high intake.

Pregnancy and breastfeeding

Eating parsley as a food (small culinary amounts in salads, tabbouleh, garnish on cooked dishes) is fine during pregnancy and a normal part of many cuisines. Concentrated parsley- extract supplements at high doses are best avoided in pregnancy because of the apiole / myristicin content of the essential-oil fraction and the historical use of parsley essential oil as an emmenagogue / abortifacient. Parsley essential oil itself is contraindicated in pregnancy. Talk to your midwife or pharmacist before starting any new supplement during pregnancy.

Parsley as a food is compatible with breastfeeding. Traditional use suggests parsley may decrease milk supply at high intake — evidence is anecdotal and weak — so if you are establishing breastfeeding or struggling with supply, talk to your midwife or health visitor before adding a concentrated parsley supplement.

Talk to your GP, midwife, or pharmacist before starting any supplement during pregnancy or breastfeeding.

More clinical detail (for clinicians and informed readers)

Contraindications

  • Known parsley or Apiaceae-family (carrot / celery / fennel) allergy.
  • Pregnancy: parsley essential oil is contraindicated. Concentrated parsley-extract supplements are best avoided. Culinary leaf is fine.
  • Active kidney disease with fluid restriction — discuss with your renal team.

Drug interactions

  • Warfarin (vitamin K antagonist): parsley is a high vitamin K1 source. Consistency of intake matters more than avoidance. Discuss substantial intake changes with your anticoagulation clinic.
  • Diuretics: theoretical additive effect at high parsley intake; clinical significance at food-supplement doses is low but disclose.
  • Some laboratory tests can be affected by high vitamin K intake — tell your healthcare team.

This is not an exhaustive list. Always tell your prescriber and pharmacist about every supplement you take.

Common side effects

  • Generally well-tolerated at culinary and food-supplement doses.

Rare side effects

  • Photosensitivity reactions reported at very high intake (apiole / furanocoumarin photosensitisation).
  • Allergic reactions — rare; cross-reactivity within Apiaceae (carrot, celery, fennel, cumin) family allergies is theoretically possible.

How to take it

Typical supplemental range
Culinary doses (small handful of fresh chopped parsley) are not associated with measurable supplement-class clinical effects. Food-supplement parsley leaf powders are typically 200–500 mg per portion; clinical trial doses vary and have not converged on a standard dose for any outcome.
Timing
No specific timing requirement.

How to spot quality

Look for

  • Variety / species declared (Petroselinum crispum); flat-leaf vs curly is a culinary distinction, not a regulatory one.
  • Country of origin declared.
  • GMP-certified manufacture.
  • Vitamin K1 content declared if the product targets vitamin K claims (regulatory honesty if the product is going to be consumed by warfarin patients).
  • No mention of "essential oil" content — food-supplement parsley should be whole-leaf or whole-leaf powder.

Red flags

  • Generic "parsley extract" with no botanical declaration.
  • Claims of "diuretic", "abortifacient", "kidney cleanser", "alkalising", or any cleanse / purification framing.
  • High apiole or essential-oil framing on a food-supplement label — this is not the food-supplement tier.
  • No vitamin K1 transparency on a parsley-marketed product.

Commonly combined with

Other ingredients that share a biological pathway, cofactor relationship, or evidence-backed protocol with this one. Mechanisms below cite primary physiology — not folk pairing. Doses are literature ranges, not recommendations. Talk to your pharmacist or GP before changing your stack, especially if you take prescription medication.

Vitamin C

Strong evidence

Parsley contributes botanical vitamin C; vitamin-c entry covers dose / NRV / authorised claims.

Vitamin C from parsley enters the same plasma pool as vitamin C from any other source. Authorised UK claims attach to milligrams of vitamin C per portion.

Evidence: UK Article 14 vitamin C health claims (NHCR). [5]

Doses studied: Parsley + rosehip + acerola + ascorbic acid blends are common in gummy and tablet formats. Camden NB-553 uses this approach.

Found in Camden: Purifera™ Vitamin C Acerola Immune Complex 120 Capsules

Related ingredients

Verifera™ is published by Camden Medicals — a UK supplement retailer. We have a commercial interest in some of the ingredients described here; we declare it on every page and our editorial process forbids adjusting copy to favour our own products. Read our editorial policy.

This page is information, not medical advice. Talk to your pharmacist or GP before starting any supplement, especially if you take prescribed medicines, are pregnant or breastfeeding, or have an existing condition.

Suspected side effects can be reported to the MHRA via the Yellow Card scheme: yellowcard.mhra.gov.uk