Hawthorn berries for dogs: a traditional herb, heart health and precautions

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Hawthorn is one of those plants you might walk past in autumn without noticing. The shrub or small tree bears red berries, yet in many gardens these are left for the birds. When I started looking into traditional uses of hawthorn, I soon found myself reading about heart health. Hawthorn has a long history in human herbal medicine and is also familiar in integrative veterinary practice.

Two questions interest me. Does hawthorn contain compounds with real biological effects on the heart and blood vessels? And does that mean we can simply grind berries into the food of a dog with heart disease? There are serious lines of research addressing the first question. The second calls for considerably more care.

What is hawthorn, and which parts are actually used?

Hawthorns belong to the genus Crataegus. There are many species and hybrids, and not all herbal preparations are alike. Traditional herbal medicine uses fruits, leaves and flowers; studies have often used standardised leaf-and-flower extracts instead. Eating the berries is not equivalent to taking an extract with a defined active-compound content.

Hawthorn contains various polyphenols, including flavonoids and proanthocyanidins. Laboratory studies have associated them with antioxidant activity and functions of blood vessels and heart cells. This provides a basis for studying potential circulatory effects. But the word “antioxidant” does not itself prove that berries slow aging or prevent heart disease in dogs.

If gathering berries yourself, first identify the plant correctly. Avoid fruit growing beside roads or on treated land. Seeds and hard parts are not something a dog should gulp down. The berries are traditionally used dried or as an infusion, but the amount depends greatly on the plant and preparation method.

Why is hawthorn associated with the heart?

Research has explored possible effects on vascular tone, blood flow and the processes involved in cardiac contraction. Some studies were conducted in laboratories or experimental animals and others in humans. Herbal practitioners frequently describe hawthorn as a heart-supporting plant, especially for milder functional complaints.

A 2008 Cochrane review analysed, among other data, ten trials involving 855 people with chronic heart failure. Most used hawthorn extract alongside conventional treatment. Improvements appeared in some measures of exercise tolerance and symptoms. There was insufficient evidence, however, to determine whether treatment prolonged life or reduced serious cardiac events. These were human trials, not studies of berries fed to dogs.

The European Medicines Agency’s herbal guidance similarly addresses particular hawthorn leaf-and-flower preparations and traditional uses in people. It is not a veterinary dosing guideline. Still less can we conclude that a teaspoon of dried berries has the same effect as the standardised extract used in a clinical trial.

What does hawthorn not establish about a dog’s heart?

Heart failure in dogs is not a single disease. Valve disease, heart muscle disease and arrhythmias can all cause different problems and require different monitoring and medication. A possible effect of hawthorn on blood vessels tells us little about survival in a dog with mitral valve disease or heart rate in a dog with atrial fibrillation.

Integrative herbal practice sometimes recommends hawthorn together with dandelion leaf, referring to possible support for fluid balance. Herbalist Joyce Belcher, for example, has described this approach. It is based on traditional use, but an important limit applies: if a dog with heart failure is coughing or struggling to breathe because fluid has accumulated in the lungs or abdomen, prescribed diuretics cannot be replaced with herbal tea. Fluid overload in heart failure can quickly become life-threatening.

It is also too great a leap to claim hawthorn heals a heart damaged by heartworms, infection or chemotherapy. Possible cellular effects merit investigation, but demonstrating a treatment benefit would require studies in those actual patients. It makes little sense to group these different illnesses into a single claim that “hawthorn helps the heart”.

Could hawthorn support digestion or help with restlessness?

Traditional use has linked hawthorn fruit with digestive support. The berries contain fibre and plant compounds that may influence the gut. But we do not know enough about how much a dog would need for a meaningful clinical effect. We certainly cannot say that hawthorn reliably replaces a prebiotic or treats diarrhoea.

The same applies to anxiety, antibacterial properties and anti-cancer potential. Laboratory research and studies in other species raise questions worth pursuing, but do not prove that hawthorn berries are an anxiety medication, antibiotic or cancer treatment for dogs. I do not want to discard possible mechanisms, nor promise more than the evidence allows.

Berries, powder or tea: what about the amount?

One practical traditional guideline is approximately one teaspoon of ground berries per 450 g of food, or one teaspoon of dried berries per cup of hot water. An essential qualification: these are examples of traditional use, not doses clinically established as safe or effective in dogs. Even “one teaspoon” does not define the active-compound quantity, which varies with species, grinding and drying.

Offering a healthy dog a small amount of clean, properly identified berry flesh for dietary variety is very different from giving a dog with heart disease a concentrated herbal preparation every day. With heart disease, low blood pressure, kidney problems or ongoing medication, I would not experiment with doses independently. Safety information is especially limited in pregnancy.

Drug interactions: precision matters here

The very possibility of cardiovascular effects makes interactions important. A dog may already take blood-pressure medicines, pimobendan to support cardiac contraction, a diuretic or an antiarrhythmic. Digoxin also warrants caution. One small human study found no significant pharmacokinetic interaction between digoxin and a particular hawthorn extract, but that does not demonstrate the safety of every hawthorn species, herbal mixture or combination in dogs.

For a dog diagnosed with heart disease, it makes sense to know the exact diagnosis, medications, blood pressure, kidney values and, if possible, heart rhythm before considering a herbal supplement. A single study or someone’s positive experience does not replace these facts.

Hawthorn is a good example of why traditional herbal practice and modern science need not be opposites. Tradition can point us toward useful research questions, and some human studies add weight to those questions. But treating a dog with heart disease requires a different standard of evidence and safety from gathering a few autumn berries in the garden. That distinction makes the use of plants more informed, not less interesting.

Sources

• Guo R, Pittler MH, Ernst E (2008). Hawthorn extract for treating chronic heart failure. Cochrane Database of Systematic Reviews. DOI.
• National Center for Complementary and Integrative Health (NCCIH). Hawthorn: Usefulness and Safety.
• European Medicines Agency. Crataegi folium cum flore: European Union herbal monograph; leaf and flower preparations in humans.
• American Heart Association. Complementary and Alternative Medicines for Heart Failure; context on drug interactions.
• Merck Veterinary Manual. Cardiac Medications of Dogs and Cats; clinical use of cardiac medications.
• Dogs Naturally Magazine. Hawthorn: Help Your Dog’s Heart; integrative herbal perspective.