Many people in the UK seek natural alternatives to conventional allergy medications, turning to herbal supplements for relief from hay fever, eczema, and other allergic conditions. Whilst herbal remedies have traditional use across various cultures, it's important to understand that 'natural' does not automatically mean safe or effective. Herbal supplements are regulated differently from licensed medicines in the UK, and the evidence supporting their use for allergies varies considerably. This article examines commonly used herbal supplements for allergy management, reviews the scientific evidence, discusses safety considerations, and explains when professional medical advice is essential for effective allergy treatment.

Understanding Allergies and Natural Treatment Approaches

Allergies occur when the immune system overreacts to normally harmless substances such as pollen, dust mites, pet dander, or certain foods. This hypersensitivity triggers the release of histamine and other inflammatory mediators, leading to symptoms ranging from sneezing and itching to more severe reactions. In the UK, allergic conditions such as hay fever, eczema, and food allergy affect a substantial proportion of the population, making allergy management a significant public health concern.

Conventional allergy treatments typically include antihistamines, corticosteroids, and allergen immunotherapy. However, some individuals seek complementary approaches, including herbal supplements, either due to concerns about medication side effects, personal preference for natural remedies, or as adjuncts to conventional treatment. It is important to understand that whilst herbal supplements are derived from natural sources, this does not automatically mean they are safer or more effective than licensed medicines.

The appeal of herbal remedies lies partly in their traditional use across various cultures for centuries. However, the regulatory framework for herbal supplements differs significantly from that of licensed medicines. In the UK, herbal products may be sold as food supplements (which cannot legally make medicinal claims) or under the Traditional Herbal Registration (THR) scheme administered by the MHRA. The THR mark confirms that a product meets quality and safety standards and has evidence of traditional use, but it does not establish clinical efficacy in the way that licensing of conventional medicines does.

Key considerations when exploring natural approaches include:

• Understanding that 'natural' does not equal 'risk-free'

• Recognising that herbal supplements can interact with prescribed medications

• Acknowledging that evidence quality varies considerably between different herbal products

• Maintaining realistic expectations about treatment outcomes

• Being aware that many herbal products lack robust clinical trial evidence for allergic conditions

Anyone considering herbal supplements for allergy management should approach this decision with the same careful consideration they would give to any therapeutic intervention, ideally in consultation with a healthcare professional such as a GP or pharmacist.

Herbal Supplements Commonly Used for Allergy Relief

Several herbal supplements have gained popularity for managing allergic symptoms, though the evidence supporting their use varies considerably and most are not recommended in UK clinical guidelines. Butterbur (Petasites hybridus) has been studied for allergic rhinitis, with extracts thought to have anti-inflammatory properties. However, raw butterbur contains pyrrolizidine alkaloids (PAs), which are hepatotoxic and can cause serious liver damage. Due to safety concerns, butterbur products for internal use are not licensed or registered under the THR scheme in the UK, and the MHRA and European Medicines Agency have issued warnings about PA-containing herbal products. Butterbur is generally not recommended for allergy management.

Quercetin, a flavonoid found in onions, apples, and berries, is available as a concentrated supplement. Laboratory studies suggest it may stabilise mast cells and reduce histamine release, but high-quality human clinical evidence for allergic rhinitis remains limited. Quercetin is often combined with bromelain, an enzyme from pineapple, which may enhance absorption and provide additional anti-inflammatory effects, though clinical benefits are unproven.

Stinging nettle (Urtica dioica) has traditional use for hay fever symptoms. Freeze-dried nettle leaf preparations are thought to interfere with inflammatory pathways, though the exact mechanism remains unclear. Evidence is limited to small studies of variable quality, and robust clinical trials are lacking.

Perilla (Perilla frutescens), used in traditional Asian medicine, contains rosmarinic acid and other compounds with potential anti-allergic properties. Evidence is preliminary, based on small studies, and insufficient to support routine use.

Other supplements sometimes used include:

• Vitamin C – sometimes claimed to have antihistamine effects, but evidence for benefit in allergic rhinitis is limited and inconsistent

• Probiotics – may modulate immune responses; some studies suggest certain strains might reduce symptom severity in allergic rhinitis, but results are inconsistent and strain-specific. Probiotics are not recommended by NICE for the prevention of allergic conditions in children

• Omega-3 fatty acids – have anti-inflammatory properties, but evidence for benefit in allergic rhinitis is limited and inconsistent

• Spirulina – a blue-green algae with suggested immunomodulatory effects, but evidence for allergic rhinitis is preliminary and insufficient

It is crucial to note that the quality, purity, and potency of herbal supplements can vary significantly between manufacturers, as they are not subject to the same stringent quality controls as licensed medicines. NICE guidance on allergy management does not recommend herbal supplements as treatment for allergic conditions.

Evidence for Herbal Remedies in Managing Allergy Symptoms

The scientific evidence supporting herbal supplements for allergy management is limited, with most remedies lacking the robust, large-scale clinical trials required to establish definitive efficacy. Butterbur has been studied in several randomised controlled trials, some suggesting that PA-free extracts may reduce seasonal allergic rhinitis symptoms. However, these studies were generally small, of short duration, and methodological quality varied. Importantly, safety concerns regarding liver toxicity—even with products labelled 'PA-free'—have led to regulatory restrictions in the UK and Europe. The MHRA and European Medicines Agency have issued warnings about pyrrolizidine alkaloid-containing herbal products, and butterbur preparations for internal use are not licensed or registered under the THR scheme in the UK. The potential risks are considered to outweigh any possible benefit.

Quercetin shows promise in laboratory and animal studies, where it demonstrates mast cell stabilisation and reduced histamine release. However, human clinical trials are limited, often small-scale, and of variable methodological quality. Systematic reviews have found insufficient high-quality evidence to recommend quercetin for allergic rhinitis.

For stinging nettle, a small randomised controlled trial suggested freeze-dried nettle was rated higher than placebo for allergy relief, but the study size and quality limit firm conclusions. Much of the evidence remains anecdotal or based on traditional use rather than rigorous clinical investigation.

Probiotics have generated research interest, particularly for allergic rhinitis. Some studies suggest certain probiotic strains may reduce symptom severity and improve quality of life, possibly by modulating gut microbiota and immune function. However, results are inconsistent, benefits appear strain-specific, and probiotics are not recommended by NICE for the prevention or treatment of allergic conditions.

The evidence for other supplements such as spirulina, perilla, vitamin C, and omega-3 fatty acids in allergic rhinitis remains preliminary and insufficient. Whilst some small studies report positive findings, these often suffer from methodological weaknesses including small sample sizes, lack of blinding, or inadequate control groups.

Important limitations of the current evidence include:

• Variability in herbal preparation methods, dosing, and product quality

• Short study durations and small sample sizes

• Publication bias favouring positive results

• Lack of long-term safety data

• Difficulty comparing studies due to different outcome measures

• Absence of head-to-head comparisons with licensed medicines

NICE guidance on allergy management does not currently recommend herbal supplements as treatment for allergic conditions, reflecting the limited and inconsistent evidence base compared to conventional therapies with proven efficacy and safety profiles.

Safety Considerations When Using Herbal Supplements for Allergies

Whilst herbal supplements are often perceived as safe due to their natural origin, they can pose significant risks and are not suitable for everyone. Hepatotoxicity (liver damage) is a particular concern with certain herbs. Butterbur, even in products labelled 'PA-free', has been associated with serious liver injury in some cases. Due to the risk of pyrrolizidine alkaloid-related hepatotoxicity and the lack of UK-licensed or THR-registered internal preparations, butterbur is not recommended for use. The MHRA and European Medicines Agency have issued public health warnings about PA-containing herbal products. Anyone with existing liver disease should avoid herbal supplements that carry hepatotoxicity risk. If you develop signs of liver injury whilst taking any herbal supplement—such as jaundice (yellowing of the skin or eyes), dark urine, pale stools, or persistent upper abdominal pain—stop the product immediately and seek urgent medical assessment.

Drug interactions represent another important safety consideration. Herbal supplements can interact with prescribed medications through various mechanisms, including affecting drug metabolism via cytochrome P450 enzymes. For example, quercetin may theoretically interact with certain antibiotics and anticoagulants, though clinical significance is not well established. St John's wort, sometimes used for various conditions, is well known for reducing the effectiveness of numerous medications including oral contraceptives, anticoagulants, and immunosuppressants.

Allergic reactions to herbal supplements themselves can occur. Individuals with pollen allergies may experience cross-reactivity with certain plant-based supplements due to shared proteins between related plant species. For instance, those allergic to plants in the Asteraceae family (such as ragweed) might react to herbal products from the same family, including chamomile or echinacea. This can paradoxically worsen symptoms in those seeking allergy relief. (Note: this is distinct from oral allergy syndrome, also called pollen–food allergy syndrome, which typically involves reactions to raw fruits, vegetables, or nuts in individuals with pollen allergy.)

Quality and contamination issues are significant concerns in the herbal supplement market. Products may contain:

• Incorrect plant species or plant parts

• Contaminants including heavy metals, pesticides, or microbial contamination

• Undeclared pharmaceutical ingredients

• Variable amounts of active compounds between batches

• Allergens not listed on labels

In the UK, look for products with a Traditional Herbal Registration (THR) mark, which provides some quality assurance, though this does not guarantee efficacy or suitability for your condition.

Special populations require particular caution. Pregnant and breastfeeding women should avoid most herbal supplements due to insufficient safety data. Children should not be given herbal remedies without medical supervision. Those with existing medical conditions, particularly liver or kidney disease, should consult their GP before using any herbal supplement.

Always inform your GP and pharmacist about any herbal supplements you are taking, as they need this information to assess potential interactions with prescribed treatments and to monitor for adverse effects. If you experience a suspected side effect from a herbal or food supplement, you can report it via the MHRA Yellow Card scheme at yellowcard.mhra.gov.uk or through the Yellow Card app.

When to Seek Medical Advice for Allergy Management

Whilst mild allergic symptoms may be managed with over-the-counter treatments, certain situations require prompt medical assessment. Immediate medical attention (call 999) is necessary if you experience signs of anaphylaxis, including difficulty breathing, swelling of the face or throat, rapid pulse, dizziness, feeling faint, or loss of consciousness. If you have been prescribed an adrenaline auto-injector (such as an EpiPen), use it immediately as instructed, then call 999. Anaphylaxis is a medical emergency requiring immediate treatment with adrenaline.

You should contact your GP if:

• Allergy symptoms significantly impact your daily activities, sleep, or quality of life

• Over-the-counter antihistamines or other treatments are ineffective

• Symptoms persist for more than a few weeks or worsen over time

• You are unsure what is triggering your allergic reactions

• You experience frequent or severe allergic reactions

• You are considering herbal supplements and have existing medical conditions or take regular medications

• You develop new symptoms whilst taking herbal supplements, particularly signs of liver problems such as jaundice (yellowing of skin or eyes), dark urine, pale stools, or persistent upper abdominal pain

Your GP can provide a thorough assessment, including a detailed history of your symptoms and potential triggers. In primary care, your GP may arrange a blood test to measure specific IgE antibodies to suspected allergens. If symptoms are severe, difficult to control, or the diagnosis is uncertain, your GP may refer you to an allergy specialist. Skin prick testing is typically performed in specialist allergy clinics in secondary care. NICE recommends that individuals with suspected allergy should have a structured clinical assessment and, where appropriate, allergy testing to guide management.

Before starting any herbal supplement, it is advisable to discuss this with your GP or pharmacist, particularly if you:

• Take prescribed medications

• Have existing health conditions, especially liver or kidney disease

• Are pregnant, breastfeeding, or planning pregnancy

• Are considering giving supplements to children

Healthcare professionals can help you weigh the potential benefits against risks and ensure that herbal supplements do not interfere with other treatments. They can also help you access evidence-based treatments that have been proven effective for allergy management.

Remember that effective allergy management often requires a comprehensive approach, including identifying and avoiding allergen triggers where possible, appropriate use of medications when needed, and in some cases, allergen immunotherapy. Herbal supplements, if considered at all, should be discussed with a healthcare professional and viewed as unproven adjuncts rather than replacements for evidence-based treatments. Always seek professional guidance to ensure safe and effective management of your allergic condition.

Frequently Asked Questions