Hawthorn

Crataegus is a large genus of thorny shrubs and small trees in Rosaceae, the rose family, growing in temperate regions throughout the world (NCCIH). Medicinal hawthorn is not one species. The European Pharmacopoeia definition, quoted by EMA, covers the flower-bearing branches of Crataegus monogyna Jacq. (Lindm.), common or single-seeded hawthorn, and Crataegus laevigata (Poir.) DC., Midland hawthorn, whose older synonyms include C. oxyacanthoides and C. oxyacantha, the name that appears in many older studies. It also accepts their hybrids and, more rarely, other European species including C. pentagyna, C. nigra, and C. azarolus. NCBI Taxonomy files C. monogyna as taxon 140997 and C. laevigata as 298643. The two main species are told apart by their leaves and flowers: C. monogyna has deeply cut leaves with three or five pointed lobes and a single carpel, so one seed per fruit; C. laevigata has shallower leaves with three to seven blunt lobes and two or three carpels. Both bear clusters of small white five-petalled flowers with many stamens in spring, followed by red haws.

Two quite different preparations go by the name hawthorn. European herbal medicine, the EU monograph, and nearly all modern clinical trials use the leaf with flower (Crataegi folium cum flore). The European Pharmacopoeia requires the dried herb to contain at least 1.5% flavonoids, expressed as hyperoside, and sets minimum flavonoid levels for aqueous and hydroalcoholic extracts (EMA). The best-studied product, WS 1442, is a dry extract of leaves with flowers made with 45% ethanol and adjusted to 17.3–20.1% oligomeric procyanidins (Holubarsch, 2018). The berries, or haws, are the other tradition: Walker and colleagues note that UK herbal practitioners use leaves, flowers, and berries, Commission E’s 1984 monograph covered the fruit as well as leaf and flower, and an Austrian product combining leaf-and-flower and fruit extract has been sold since 1954 (EMA). In Asia hawthorn is known as shan zha and is used in traditional Chinese medicine for digestion and appetite as well as cardiovascular complaints (MSKCC); NCCIH lists Chinese hawthorn (C. pinnatifida) among the species sold. Berry preparations have far less clinical evidence, and the current EU monograph covers leaf and flower only.

EMA lists the main constituents of leaf and flower as flavonoids, mostly glycosides such as vitexin, vitexin-2″-O-rhamnoside, isovitexin, hyperoside, and quercetin; flavan compounds including catechin, epicatechin, and oligomeric and polymeric procyanidins; triterpenic acids; amines such as phenethylamine; and phenolic acids such as caffeic and chlorogenic acid. Hyperoside (PubChem CID 5281643, C21H20O12), a quercetin glycoside, is the marker the Pharmacopoeia uses to express flavonoid content. Older German monographs defined effective doses by flavonoid or procyanidin content, which is why product labels may quote either. Mexican hawthorn (C. mexicana), sold as tejocote, is a different species whose root has been marketed for weight loss, a use with no evidence (NCCIH).

EMA’s assessment report traces hawthorn in European medicine to Dioscorides in the first century AD, after which it became a fixture of folk medicine as a heart tonic. Medieval and early modern use is documented in German pharmacognosy texts: Quercetanus (1544–1609), physician to King Henry IV of France, is said to have made an anti-ageing syrup from the plant. Folk traditions recorded by EMA vary widely: flower tea for raised blood pressure in Germany, a sedative in Poland, a treatment for jaundice in Hungary, and remedies for cough, urinary complaints, and a warm pain-relieving compress in parts of Czechoslovakia. NCCIH adds traditional uses for digestion, circulation, and kidney and bladder problems, and on the skin for sores, itching, and frostbite.

Hawthorn’s reputation as a cardiac drug is surprisingly modern. EMA records that an Irish doctor named Green treated many heart patients with it in the second half of the nineteenth century, and that his remedy became known only after his death in 1894. From 1896 it was used in America for heart disease and angina, to support the effect of digitalis, or when digitalis was not tolerated. A 1953 German codex cited by EMA lists combinations with other cardioactive plants, including foxglove, strophanthus, oleander, and belladonna. In traditional Chinese medicine, where it is known as shan zha, hawthorn is used to improve digestion, stimulate appetite, and treat cardiovascular conditions (MSKCC).

Germany formalized hawthorn as a heart medicine. Commission E monographs of 1984 and 1994 endorsed hawthorn preparations for declining cardiac performance; the 1994 version specified extracts at 160–900 mg a day in two or three doses for at least six weeks, for heart failure of NYHA class II (EMA). WS 1442 became the most studied extract, culminating in the SPICE trial, published in 2008, the same year as Cochrane’s positive review; the HERB CHF trial followed in 2009. When the EU’s herbal committee assessed hawthorn, it concluded that the earlier studies, which measured surrogate outcomes such as exercise capacity, no longer proved efficacy. Its monograph, adopted on 5 April 2016, grants only traditional use, drawing on more than 30 years of use in France for palpitations and mild sleep problems.

Laboratory studies describe heart effects that make hawthorn’s reputation plausible. EMA’s assessment cites positive inotropic effects in isolated human heart muscle, meaning stronger contraction, along with improved force at higher heart rates. Proposed mechanisms include inhibition of the sodium-potassium pump (Na+/K+-ATPase), which raises calcium inside heart cells, the same target as digoxin, and inhibition of phosphodiesterase, which slows the breakdown of cyclic AMP. MSKCC attributes activity to flavonoids and oligomeric procyanidins and adds vasodilation, increased blood flow to the heart muscle, reduced afterload, and antioxidant effects. EMA also describes animal studies suggesting protection against ischaemia and reperfusion injury.

The overlap with digoxin is why interactions are a theoretical concern: one laboratory study found that two hawthorn extracts raised calcium in heart cells but added nothing to digoxin’s effect, suggesting they may act at the same site (EMA). Laboratory heart effects have not translated into fewer cardiac events in patients. In SPICE, a subgroup with less severely impaired hearts had fewer sudden cardiac deaths on hawthorn, which has fuelled interest in antiarrhythmic effects, but a subgroup finding in a trial that missed its main end point proves nothing on its own.

On other systems, MSKCC notes laboratory evidence that hawthorn flowers inhibit thromboxane A2, a platelet signal, and that hawthorn may induce the drug-metabolizing enzyme CYP3A4 by activating the pregnane X receptor, both of unknown clinical relevance. In a small crossover study reviewed by EMA, with aspirin as the comparator, 800 mg of powdered leaf and flower three times daily had no effect on platelet aggregation or thromboxane production in 16 healthy volunteers.

Chronic heart failure, symptoms and exercise: Pittler, Guo, and Ernst (Cochrane 2008) included 14 double-blind, placebo-controlled trials of hawthorn leaf-and-flower extracts, mostly used as an add-on to conventional treatment. Ten trials with 855 patients in NYHA classes I to III could be pooled. Hawthorn improved maximal workload (by about 5 watts), exercise tolerance, and the pressure–heart rate product, an index of the heart’s oxygen use, and reduced symptoms such as shortness of breath and fatigue. Apart from one trial that reported deaths (three on hawthorn, one on placebo) without details, no trial reported mortality or cardiac events. EMA later judged that such surrogate measures are no longer sufficient evidence for a heart failure treatment.

Heart failure, hard outcomes: in SPICE, Holubarsch and colleagues (European Journal of Heart Failure 2008) randomized 2,681 adults with NYHA class II or III heart failure and an ejection fraction of 35% or less to WS 1442, 900 mg a day, or placebo for 24 months, on top of optimal medicines. Time to first cardiac event did not differ (event rates 27.9% and 28.9%; hazard ratio 0.95), and the trend towards lower cardiac mortality was not significant. In patients with an ejection fraction of 25% or more, sudden cardiac death was 39.7% lower, a subgroup result that needs confirmation. In HERB CHF, Zick and colleagues (European Journal of Heart Failure 2009) randomized 120 patients to 450 mg twice daily or placebo for six months alongside standard therapy and found no difference in six-minute walk distance, quality of life, or functional measures, with a modest ejection fraction difference and more adverse events, mostly non-cardiac, on hawthorn. A secondary analysis by the same group found hawthorn did not reduce progression and appeared to increase the early risk of worsening heart failure.

Regulators and reviewers disagree on what this means. EMA concluded that hawthorn achieves no statistically significant benefit over placebo in heart failure, that guideline treatment is mandatory in a condition with high mortality, and that the benefit–risk balance for hawthorn as heart failure therapy is negative. A 2018 review of WS 1442 by SPICE investigators, who received honoraria from the manufacturer, judged its benefit–risk positive. NCCIH describes the evidence as conflicting and says there is not enough evidence for angina, abnormal heart rhythm, or atherosclerosis.

Blood pressure: Walker and colleagues (British Journal of General Practice 2006) randomized 79 people with type 2 diabetes, most already taking blood pressure drugs, to 1,200 mg a day of hawthorn extract or placebo for 16 weeks. Diastolic pressure fell more with hawthorn (from 85.6 to 83.0 mmHg, against no fall on placebo), but systolic pressure did not differ. Asher and colleagues (BMC Complementary and Alternative Medicine 2012) gave 21 adults with high-normal or mildly raised blood pressure doses of 1,000–2,500 mg of a standardized extract in a crossover trial and found no dose-related effect on blood vessel function or blood pressure. MSKCC calls the data conflicting.

Traditional EU uses and other claims: EMA accepts hawthorn leaf and flower for temporary nervous heart complaints, such as palpitations or a perceived extra heartbeat due to mild anxiety, after a doctor has excluded serious conditions, and for mild symptoms of mental stress and to aid sleep. These rest on long-standing use, not trials. NCCIH says there is no evidence that hawthorn aids weight loss and that its effect on anxiety is unclear. MSKCC notes that clinical studies of hawthorn for indigestion are lacking.

EU traditional use for temporary nervous heart complaints (EMA/HMPC/159075/2014, adopted 5 April 2016), adults and the elderly: herbal tea, 1–2 g of dried leaf and flower in 150 ml of boiling water up to four times daily (maximum 6 g a day); powdered herb, 190–350 mg per dose, 570–1,750 mg a day; or a dry hydroethanolic extract (DER 4–7.1:1, 45–70% ethanol), 80–450 mg per dose, 240–900 mg a day. Liquid extracts, a tincture, a sweet-wine extract, and fresh-plant juice are also listed. Not recommended under 18 for this use. For mild stress and sleep, adolescents and adults may use powdered herb at the same doses or an aqueous dry extract (DER 4–5:1), 250 mg per dose, 750–1,000 mg a day; not recommended under 12. If symptoms last more than two weeks, see a doctor.

In clinical trials, the leaf-and-flower extract WS 1442 was given at 900 mg a day, as 450 mg twice daily in HERB CHF, and Commission E’s 1994 monograph specified 160–900 mg of extract a day for at least six weeks (EMA). The blood pressure trial by Walker used 1,200 mg a day. Products are standardized either to flavonoids, expressed as hyperoside, or to oligomeric procyanidins, so labels are not always comparable. Tinctures and liquid extracts contain alcohol, which EMA requires to be labelled.

Use hawthorn only after a diagnosis, and only with the knowledge of whoever treats your heart or blood pressure. Choose a leaf-and-flower product that names the species and the extract. Do not buy tejocote root or other weight-loss products said to contain Mexican hawthorn: the FDA has found toxic yellow oleander in products labelled as tejocote root and continues to add products to its warning, most recently in September 2026.