Hawthorn

What it is

Hawthorn is a thorny shrub or small tree of the genus Crataegus. The Cochrane review's summary page describes hawthorn extract as made from the plant's dried leaves, flowers and fruits, but the trials it pooled used leaf-and-flower extracts. The most studied product, WS 1442, is described by its manufacturer's reviewers as a dry extract of hawthorn leaves with flowers standardised to oligomeric procyanidins. Different Crataegus species are sold, and one of them, Crataegus mexicana (tejocote), has been the subject of an FDA warning about products that actually contained a different, toxic plant.

What the research says

The evidence is genuinely split. A 2008 Cochrane review of 14 double-blind placebo-controlled trials found small benefits for exercise capacity and symptoms when hawthorn leaf-and-flower extract was added to conventional heart failure treatment. But the two largest and most rigorous trials since then - SPICE (2,681 patients, 2 years) and HERB CHF (120 patients, 6 months) - found no effect on their primary endpoints, and HERB CHF recorded more adverse events in the hawthorn group. A 2025 meta-analysis of six small trials reported lower systolic and diastolic blood pressure, but the confidence intervals it printed for both outcomes cross zero, so its headline claim of a clinically significant effect is not supported by its own numbers, and its authors said larger trials are needed. Hawthorn is not a nutrient; nobody can be deficient in it.

Evidence grade: Disputed.

What goes wrong

The same Cochrane review recorded adverse events that were infrequent and short-lived, including nausea, dizziness and cardiac and gastrointestinal complaints. (Source 1)

• Systematic review, Low certainty.
• Size: 14 included trials.
• Who: adults with chronic heart failure in placebo-controlled trials.
• How long: short-term trials.
• Result: no rates given in the summary retrieved; events described as infrequent, mild and transient.
• Funding: not stated in the summary retrieved.

Limit of this finding: This review only accepted trials of hawthorn leaf-and-flower extract monopreparations, yet the same review's plain-language summary describes hawthorn extract as made from the dried leaves, flowers and fruits of the hawthorn bush. The two statements do not match. Read the result as applying to standardised leaf-and-flower extracts only; it is not evidence about berry or fruit products sold as hawthorn.

Reported adverse events were infrequent, mild, and transient; they included nausea, dizziness, and cardiac and gastrointestinal complaints.

HERB CHF recorded significantly more adverse events in the hawthorn arm than in the placebo arm. (Source 2)

• Randomized trial, Moderate certainty.
• Size: 120 patients.
• Who: ambulatory patients with NYHA class II-III chronic heart failure.
• How long: 6 months.
• Result: significantly more adverse events in the hawthorn group, P = 0.02; most were non-cardiac.
• Funding: not stated in the abstract retrieved.

There were significantly more adverse events reported in the hawthorn group (P = 0.02), although most were non-cardiac.

The blood pressure meta-analysis reported headaches and mild gastrointestinal symptoms as the commonest adverse effects in hawthorn users. (Source 3)

• Meta-analysis, Low certainty.
• Size: six trials, 428 participants.
• Who: adults taking hawthorn preparations in placebo-controlled trials.
• How long: 10 weeks to 6 months.
• Result: no rates reported in the text retrieved; headaches and nausea named as the commonest events.
• Funding: not stated in the abstract retrieved.

The most common adverse effects were headaches and mild gastrointestinal symptoms, such as nausea, which were reported by patients using hawthorn preparations.

NCCIH lists dizziness, nausea, vomiting, diarrhoea and muscle pain as side effects of hawthorn. (Source 4)

• Official position, Certainty not rated.
• Size: not applicable; agency summary.
• Who: people taking hawthorn supplements.
• How long: position current as of April 2025.
• Result: no rates given on the page retrieved.
• Funding: US government agency.

Side effects of hawthorn can include dizziness, nausea, vomiting, diarrhea, and muscle pain.

In January 2024 the FDA identified supplements labelled as tejocote root, a Crataegus species, that actually contained yellow oleander, a toxic plant. (Source 5)

• Official position, Certainty not rated.
• Size: a list of products; count not given in the summary retrieved.
• Who: consumers of products labelled tejocote root (Crataegus mexicana)
• How long: FDA list published January 2024.
• Result: no incidence figures in the summary retrieved; the substituted plant is described as toxic to the nervous system, heart, stomach and intestines.
• Funding: US government agency.

that actually contain yellow oleander, a toxic plant known to cause harm to the nervous system, heart, stomach, and intestines

What the evidence supports

A Cochrane review of double-blind placebo-controlled trials found a small increase in maximal workload with hawthorn extract added to conventional heart failure treatment. (Source 6)

• Systematic review, Low certainty.
• Size: 14 trials met inclusion criteria; 10 trials with 855 patients pooled; maximal workload analysis n = 380.
• Who: adults with chronic heart failure, mostly NYHA class II-III, on conventional treatment.
• How long: trials were short-term (weeks to a few months)
• Result: weighted mean difference in maximal workload 5.35 Watt, 95% CI 0.71 to 10.00, P < 0.02, n = 380.
• Funding: not stated in the summary retrieved.

Limit of this finding: This review only accepted trials of hawthorn leaf-and-flower extract monopreparations, yet the same review's plain-language summary describes hawthorn extract as made from the dried leaves, flowers and fruits of the hawthorn bush. The two statements do not match. Read the result as applying to standardised leaf-and-flower extracts only; it is not evidence about berry or fruit products sold as hawthorn.

For the physiologic outcome of maximal workload, treatment with hawthorn extract was more beneficial than placebo (WMD (Watt) 5.35, 95% CI 0.71 to 10.00, P < 0.02, n = 380).

What the evidence does not support

In the largest hawthorn trial ever run, SPICE, hawthorn extract WS 1442 did not delay the first cardiac event compared with placebo. (Source 7)

• Randomized trial, Moderate certainty.
• Size: 2681 patients randomised (WS 1442: 1338; placebo: 1343)
• Who: adults with NYHA class II or III congestive heart failure and left ventricular ejection fraction 35% or less, on optimal medication.
• How long: 24 months.
• Result: mean time to first cardiac event 620 days with WS 1442 vs 606 days with placebo; event rates 27.9% vs 28.9%; hazard ratio 0.95, 95% CI 0.82 to 1.10, p=0.476; cardiac mortality HR 0.89, 95% CI 0.73 to 1.09, p=0.269.
• Funding: not stated in the abstract retrieved.

Average time to first cardiac event was 620 days for WS® 1442 and 606 days for placebo (event rates: 27.9% and 28.9%, hazard ratio (HR): 0.95, 95% CI [0.82;1.10]; p=0.476).

The SPICE authors themselves concluded the extract had no significant effect on the trial's primary endpoint, with a possible sudden-death signal only in a subgroup. (Source 8)

• Randomized trial, Moderate certainty.
• Size: 2681 patients.
• Who: adults with NYHA class II or III heart failure on optimal medication.
• How long: 24 months.
• Result: primary endpoint not met; in the subgroup with LVEF 25% or more, sudden cardiac death reduced by 39.7% (HR 0.59, 95% CI 0.37 to 0.94, p=0.025), a subgroup result the authors framed as only a possible indication.
• Funding: not stated in the abstract retrieved.

In this study, WS® 1442 had no significant effect on the primary endpoint.

In the HERB CHF trial, hawthorn added to modern heart failure therapy produced no improvement in walking distance, quality of life, functional capacity, neurohormones or markers of oxidative stress and inflammation. (Source 2)

• Randomized trial, Moderate certainty.
• Size: 120 ambulatory patients.
• Who: patients aged 18 years or older with NYHA class II-III chronic heart failure on conventional therapy.
• How long: 6 months.
• Result: change in 6 minute walk distance P = 0.61; no differences in quality of life, functional capacity, neurohormones, oxidative stress or inflammation; a modest difference in left ventricular ejection fraction favoured hawthorn (P = 0.04)
• Funding: not stated in the abstract retrieved.

There were no significant differences between groups in the change in 6 min walk distance (P = 0.61), or on measures of QOL, functional capacity, neurohormones, oxidative stress, or inflammation.

The HERB CHF investigators concluded hawthorn gave no symptomatic or functional benefit on top of standard heart failure therapy. (Source 9)

• Randomized trial, Moderate certainty.
• Size: 120 patients.
• Who: patients with chronic heart failure on standard medical therapy.
• How long: 6 months.
• Result: primary outcome null; authors' stated conclusion was of no benefit.
• Funding: not stated in the abstract retrieved.

Hawthorn provides no symptomatic or functional benefit when given with standard medical therapy to patients with heart failure.

Over two years in SPICE, the proportion of patients reporting adverse events was almost identical on hawthorn extract and on placebo. (Source 10)

• Expert review, not systematic, Low certainty.
• Size: 2681 patients in SPICE, summarised in a benefit-risk review.
• Who: adults with NYHA class II-III heart failure on optimal medication.
• How long: 2 years.
• Result: adverse events reported by 67.0% on WS 1442 and 68.3% on placebo, one event per 388 and 370 days of exposure respectively; serious AE rates 39.2 and 41.1%.
• Funding: not stated; review of a single manufacturer's extract, so a commercial interest should be assumed unless checked.

During the 2-year follow-up, 67.0% of the patients randomized to WS 1442 and 68.3% of those in the placebo group reported AEs, corresponding to one event in 388 and 370 days of exposure, respectively.

A benefit-risk review of the WS 1442 extract reported that no drug interaction signals had been seen in the studies covered by an earlier systematic review by Daniele and colleagues, in studies published after it, or in spontaneous reports to health authorities. (Source 11)

• Expert review, not systematic, Low certainty.
• Size: trials of WS 1442 reviewed narratively; no pooled n given.
• Who: patients in WS 1442 clinical studies, many taking digoxin, diuretics and other heart failure drugs.
• How long: studies up to 2 years.
• Result: no interaction signals observed; the review states an interaction with digoxin has been excluded.
• Funding: not stated; a single-product review, so commercial interest should be assumed unless checked.

Limit of this finding: This sentence is this review restating somebody else's review - the studies referred to are the ones in Daniele et al.'s systematic review, not studies these authors ran or searched for themselves. It is also an absence of a signal rather than a test: none of those studies was designed to detect interactions, so it does not show that hawthorn does not interact with heart medicines.

Signals for possible drug interactions with WS 1442 were not observed in any of the studies reviewed by Daniele et al., nor in those published after completion of their review, nor in literature searches that also included spontaneous reports to health authorities about suspected adverse reactions to hawthorn containing products.

Where the evidence is mixed

A 2025 meta-analysis of six small placebo-controlled trials reported lower systolic and diastolic blood pressure with hawthorn, but the confidence intervals it printed for both outcomes run from a fall to a rise, so neither result is shown to be statistically significant on the numbers as published. (Source 12)

• Meta-analysis, Low certainty.
• Size: six studies, 428 participants in total.
• Who: adults in randomised placebo-controlled trials, including people with hypertension and people with type 2 diabetes.
• How long: treatment periods of 10 weeks to 6 months.
• Result: systolic blood pressure mean difference -6.65 mmHg, 95% CI as printed [-11.72; 1.59], described by the authors as statistically significant; diastolic blood pressure mean difference -7.19 mmHg, 95% CI [-15.17; 0.79], described by the authors as non-significant; doses ranged 250-1200 mg/day.
• Funding: not stated in the abstract retrieved.

Limit of this finding: The paper contradicts itself. Its abstract calls the systolic fall statistically significant and its conclusion calls the blood pressure effect clinically significant, but both confidence intervals it prints run from a fall to a rise - systolic [-11.72; 1.59] and diastolic [-15.17; 0.79] mmHg - and an interval that spans zero is the pattern of a result that has not reached statistical significance. The paper itself also calls the diastolic change non-significant. A dropped minus sign on the systolic upper bound is a plausible printing error, but on the page as published the wording and the numbers disagree. A reader should treat this as six small trials pointing towards lower blood pressure, not as a demonstrated blood-pressure-lowering effect.

A systematic review and meta-analysis were conducted, including six studies with a total of 428 participants.

The authors of that blood pressure meta-analysis said the trial base is too small and variable to settle the question. (Source 13)

• Meta-analysis, Low certainty.
• Size: six studies, 428 participants.
• Who: adults in placebo-controlled hawthorn trials.
• How long: 10 weeks to 6 months.
• Result: one study at low risk of bias, the others with some concerns; dose range 250-1200 mg/day contributed to heterogeneity.
• Funding: not stated in the abstract retrieved.

Limit of this finding: The paper contradicts itself. Its abstract calls the systolic fall statistically significant and its conclusion calls the blood pressure effect clinically significant, but both confidence intervals it prints run from a fall to a rise - systolic [-11.72; 1.59] and diastolic [-15.17; 0.79] mmHg - and an interval that spans zero is the pattern of a result that has not reached statistical significance. The paper itself also calls the diastolic change non-significant. A dropped minus sign on the systolic upper bound is a plausible printing error, but on the page as published the wording and the numbers disagree. A reader should treat this as six small trials pointing towards lower blood pressure, not as a demonstrated blood-pressure-lowering effect.

However, larger, well-designed trials are needed to establish optimal dosing, duration, and efficacy with greater reliability.

The US National Center for Complementary and Integrative Health holds that the heart failure evidence is conflicting and that long-term safety is untested. (Source 14)

• Official position, Certainty not rated.
• Size: not applicable; agency summary.
• Who: general public.
• How long: position current as of April 2025.
• Result: no numbers given; NCCIH states no studies have tested use beyond 16 weeks.
• Funding: US government agency.

There is conflicting evidence on the effects of hawthorn in people with heart failure.

Where the research disagrees

Whether hawthorn extract helps people with chronic heart failure

• Cochrane review authors (2008), systematic review and meta-analysis of 14 double-blind placebo-controlled trials, mostly small and short: "For the physiologic outcome of maximal workload, treatment with hawthorn extract was more beneficial than placebo (WMD (Watt) 5.35, 95% CI 0.71 to 10.00, P < 0.02, n = 380)." (Source 6)
• HERB CHF investigators (2009), randomised, double-blind, placebo-controlled trial in 120 patients on contemporary therapy: "Hawthorn provides no symptomatic or functional benefit when given with standard medical therapy to patients with heart failure." (Source 9)
• SPICE investigators (2008), randomised, double-blind, placebo-controlled morbidity/mortality trial in 2,681 patients over 24 months: "In this study, WS® 1442 had no significant effect on the primary endpoint." (Source 8)
• NCCIH (April 2025), agency position: "There is conflicting evidence on the effects of hawthorn in people with heart failure." (Source 14)

How much

• Reference intake: No dietary reference intake (RDA or AI) exists for hawthorn anywhere, because it is a herbal preparation rather than an essential nutrient. NCCIH describes it only as a supplement whose short-term use may be safe. (Source 15)
• Upper limit: No tolerable upper intake level or acceptable daily intake has been set. NCCIH (April 2025) states that no research studies have tested whether hawthorn is safe for use beyond 16 weeks. (Source 15)
• Studied: SPICE gave 900 mg/day of Crataegus extract WS 1442 or placebo for 24 months to 2,681 adults with NYHA class II-III heart failure. (Source 7)
• Studied: HERB CHF randomised 120 patients to hawthorn 450 mg twice daily or placebo for 6 months. (Source 2)
• Studied: The 2025 blood pressure meta-analysis covered trials using 250-1200 mg/day for 10 weeks to 6 months. (Source 12)
• Studied: WS 1442 is characterised as a dry extract of hawthorn leaves with flowers (4-6.6:1), ethanol 45% (w/w), adjusted to 17.3-20.1% oligomeric procyanidins. (Source 16)

A common belief, and what the research shows

The belief: Hawthorn is a proven natural heart tonic that can stand in for heart failure medicines.

What the research shows: The largest trial of the best-studied hawthorn extract found no effect on its primary endpoint: "In this study, WS® 1442 had no significant effect on the primary endpoint." A 120-patient trial on modern therapy concluded that "Hawthorn provides no symptomatic or functional benefit when given with standard medical therapy to patients with heart failure." The older Cochrane review that found benefit tested hawthorn as an add-on, not a replacement, and NCCIH's position is that "There is conflicting evidence on the effects of hawthorn in people with heart failure."

Questions and answers

What is it?

Hawthorn is a thorny shrub or small tree of the genus Crataegus. The Cochrane review's plain-language summary describes hawthorn extract as made from the plant's dried leaves, flowers and fruits, although the trials that review included used leaf-and-flower extracts rather than fruit preparations. The most studied product, WS 1442, is a dry extract of leaves with flowers standardised for oligomeric procyanidins. (Source 17)

What does it do in the body?

In placebo-controlled heart failure trials pooled by Cochrane in 2008, hawthorn extract slightly increased the maximum workload people could achieve on exercise testing. The measured difference was small, about 5 Watts. Larger later trials did not reproduce functional benefit. (Source 6)

Is it good or bad for you?

Neither clearly. Short-term use of some hawthorn products appears tolerable, but the evidence of benefit is contested and nothing is known about use beyond about four months. Trials have reported dizziness, nausea, vomiting, diarrhoea and muscle pain, and one trial recorded significantly more adverse events on hawthorn than on placebo. (Source 15)

How do you get more of it?

Hawthorn is not obtained from an ordinary diet in meaningful amounts; it is taken as an extract. Trials have used 450 mg twice daily for 6 months, 900 mg/day of WS 1442 for 24 months, and 250-1200 mg/day in blood pressure studies. This describes what trials gave, not a recommendation. (Source 2)

If it is harmful, what reduces it?

There is nothing to clear from the body: hawthorn is not stored. Adverse effects recorded in placebo-controlled trials were described as infrequent, mild and transient, which implies they settle after the extract is stopped. No elimination procedure has been studied. (Source 1)

Why might someone be low in it or missing it?

Nobody is low in hawthorn. It is a plant extract used as a treatment, not an essential nutrient, so there is no normal body level and no deficiency state to explain. Someone will only have none if they are not taking a hawthorn product. (Source 17)

Which whole foods contain it or feed it?

The plant parts named on the Cochrane summary page are the dried leaves, flowers and fruits of the hawthorn bush, though the trials in that review tested leaf-and-flower extracts, not the fruit. Hawthorn berries are eaten as food and made into teas, jellies and, in Chinese and Mexican cooking, confections, but no trial has tested culinary amounts. (Source 17)

What happens if you do not have it?

Nothing happens. Because hawthorn is not a nutrient, not taking it causes no deficiency. The relevant question is only whether taking it adds anything, and on that the evidence is conflicting. (Source 14)

How can you test for it?

No validated clinical test of a person's hawthorn status exists, and none would be meaningful, since hawthorn is not a nutrient with a normal range. We searched for hawthorn biomarker, procyanidin status and Crataegus assay work and found only product-analysis methods, not tests on people. (Source 14)

We searched: WebSearch and WebFetch for hawthorn/Crataegus biomarker or status testing alongside the Cochrane review, SPICE, HERB CHF and the NCCIH hawthorn page; none describes a test of hawthorn levels in people

References

1. Cochrane Database of Systematic Reviews / cochrane.org. Hawthorn extract for treating chronic heart failure (adverse events). 2008. PMID 18254076, DOI 10.1002/14651858.CD005312.pub2. Read the source
2. European Journal of Heart Failure (abstract as deposited with Crossref). Hawthorn Extract Randomized Blinded Chronic Heart Failure (HERB CHF) Trial (methods and results). 2009. PMID 19789403, DOI 10.1093/eurjhf/hfp116. Read the source
3. Pharmaceuticals (MDPI). Hawthorn (Crataegus spp.) Clinically Significantly Reduces Blood Pressure in Hypertension: A Meta-Analysis of Randomized Placebo-Controlled Clinical Trials (adverse effects). 2025. DOI 10.3390/ph18071027. Read the source
4. National Center for Complementary and Integrative Health, US National Institutes of Health. Hawthorn: Usefulness and Safety (side effects). 2025. Read the source
5. National Center for Complementary and Integrative Health, US National Institutes of Health. Hawthorn: Usefulness and Safety (FDA warning on tejocote root products, January 2024). 2025. Read the source
6. Cochrane Database of Systematic Reviews / cochrane.org. Hawthorn extract for treating chronic heart failure (main results). 2008. PMID 18254076, DOI 10.1002/14651858.CD005312.pub2. Read the source
7. European Journal of Heart Failure (abstract as deposited with Crossref). The Efficacy and Safety of Crataegus Extract WS® 1442 in Patients with Heart Failure: The SPICE Trial (results). 2008. DOI 10.1016/j.ejheart.2008.10.004. Read the source
8. European Journal of Heart Failure (abstract as deposited with Crossref). The Efficacy and Safety of Crataegus Extract WS® 1442 in Patients with Heart Failure: The SPICE Trial (conclusions). 2008. DOI 10.1016/j.ejheart.2008.10.004. Read the source
9. European Journal of Heart Failure (abstract as deposited with Crossref). Hawthorn Extract Randomized Blinded Chronic Heart Failure (HERB CHF) Trial (conclusion). 2009. PMID 19789403, DOI 10.1093/eurjhf/hfp116. Read the source
10. American Journal of Cardiovascular Drugs (Springer) 2018;18(1):25-36. Benefit-Risk Assessment of Crataegus Extract WS 1442: An Evidence-Based Review (adverse event rates in SPICE). 2018. DOI 10.1007/s40256-017-0249-9. Read the source
11. American Journal of Cardiovascular Drugs (Springer) 2018;18(1):25-36. Benefit-Risk Assessment of Crataegus Extract WS 1442: An Evidence-Based Review (drug interactions). 2018. DOI 10.1007/s40256-017-0249-9. Read the source
12. Pharmaceuticals (MDPI). Hawthorn (Crataegus spp.) Clinically Significantly Reduces Blood Pressure in Hypertension: A Meta-Analysis of Randomized Placebo-Controlled Clinical Trials. 2025. DOI 10.3390/ph18071027. Read the source
13. Pharmaceuticals (MDPI). Hawthorn (Crataegus spp.) Clinically Significantly Reduces Blood Pressure in Hypertension: A Meta-Analysis of Randomized Placebo-Controlled Clinical Trials (conclusions). 2025. DOI 10.3390/ph18071027. Read the source
14. National Center for Complementary and Integrative Health, US National Institutes of Health. Hawthorn: Usefulness and Safety (what the science says). 2025. Read the source
15. National Center for Complementary and Integrative Health, US National Institutes of Health. Hawthorn: Usefulness and Safety (safety). 2025. Read the source
16. American Journal of Cardiovascular Drugs (Springer) 2018;18(1):25-36. Benefit-Risk Assessment of Crataegus Extract WS 1442: An Evidence-Based Review (extract description). 2018. DOI 10.1007/s40256-017-0249-9. Read the source
17. Cochrane Database of Systematic Reviews / cochrane.org. Hawthorn extract may be used as an oral treatment option for chronic heart failure (plain language summary of the Cochrane review 'Hawthorn extract for treating chronic heart failure'). 2008. PMID 18254076, DOI 10.1002/14651858.CD005312.pub2. Read the source