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Adverse Reactions to Complementary and Alternative Medicines

Frequently Asked Questions

pdfASCIA PC Adverse Reactions Alternative Medicine FAQ 202483.84 KB

This document has been developed by ASCIA, the peak professional body of clinical immunology/allergy specialists in Australia and New Zealand. ASCIA information is based on published literature and expert review, is not influenced by commercial organisations and is not intended to replace medical advice.         For patient or carer support contact Allergy & Anaphylaxis Australia or Allergy New Zealand.

Q 1: What are complementary and alternative medicines?

Complementary and alternative medicines or therapies are sometimes used with or instead of standard medical treatment but are not considered to be standard treatment. Examples of complementary and alternative therapies include acupuncture, homeopathy, herbal medicine, dietary supplements such as vitamins and nutrition/diet.

Q 2: Do alternative medicines cause allergic reactions?

Complementary and alternative medicines are often thought to be safe, but side effects and allergic reactions can occur. Allergic reactions are most common in people with other allergic diseases, such as asthma or allergic rhinitis (hay fever). These people are often sensitive to many allergens, including those in herbal medicines.

Q 3: Can alternative medicines be used with prescribed drugs?

It is important to let your doctor know if you are taking complementary and alternative medicines. This is because these medicines can interfere with the action of prescribed drugs (medications) and side effects may occur. Complementary and alternative medicines have not always been through the extensive clinical trial and safety processes required for prescribed drugs.

Q 4: Why should I be cautious about alternative medicines?

The risk of adverse drug reactions (ADR) is increased if the complementary and alternative medicine has drug-like activity or interferes with the way the body reacts to drugs. Examples include:

  • Echinacea, milk thistle, and chamomile can interfere with some liver enzymes that play a major role in drug breakdown and detoxification by the liver. This can lead to increased side effects or reduced benefit from taking these medicines.
  • Feverfew has aspirin-like activity and may increase the risk of bleeding while taking blood thinners like warfarin or aspirin. Chamomile contains natural warfarin-like coumarins which increase the risk of bleeding in those taking warfarin as a medication.
  • Echinacea can have a short-term stimulatory effect on the immune system. Echinacea should be avoided in patients with autoimmune disease and in organ transplant patients.
  • Echinacea is thought to inhibit wound healing and should be avoided before and after surgery.

This is not a complete list of interactions. It is important to check with your doctor or pharmacist when using complementary and alternative medicines.

 Q 5: What herbal medicines contain Asteraceae?

Many herbal medicines are made from Asteraceae flowering plants, such as echinacea, dandelion, chamomile, feverfew, milk thistle, and wormwood. Exposure to these plants is common and hard to avoid. Pollen from Asteraceae plants are an important cause of allergic rhinitis (hay fever) and asthma.

Asteraceae plants include:

  • Flowering plants such as chrysanthemums, dahlias, sunflowers, marigolds, safflowers and daisies - the pollen from chrysanthemum and sunflower cause symptoms in some people who are exposed to heavy concentrations, such as flower growers.
  • Edible plants such as lettuce, safflower, chicory, and artichoke.
  • Weeds such as Ambrosia (ragweed) species, Artemisia (mugwort, sagebrush, wormwood) species, and Parthenium (feverfew), the pollen from these plants causes allergic rhinitis (hay fever), and asthma.

Q 6: What reactions have been caused by Asteraceae?

Asteraceae plants may cause contact allergic dermatitis. Echinacea, daisies, chrysanthemum, chamomile, tansy, dandelion, feverfew, and sunflowers have all been linked with contact allergy in gardeners and florists. Similar symptoms can be caused by plant extracts in cosmetics, shampoos, and massage oils. Contact with airborne plant-derived allergen can also trigger rashes in exposed skin, commonly known as Australian bush dermatitis.

Allergic sensitisation to Asteraceae pollen is linked with allergic reactions to plant-derived complementary and alternative medicines such as echinacea, royal jelly, bee pollen extracts and chamomile, as well as foods like celery, honey, sunflower seeds, carrot, lettuce, watermelon, and nuts.

In pregnancy, the use of complementary and alternative medicines containing Asteraceae should be avoided. For example, feverfew can trigger pregnancy loss in cattle and stimulate uterine contractions in pregnant women. Chamomile causes malformations in animal studies. Safflower, tansy, feverfew, calendula, chamomile, yarrow, milk thistle, and wormwood promote menstruation, stimulate uterine contraction, and can trigger abortions in animals.

Q 7: Can allergic reactions to echinacea be severe?

Echinacea is a dietary supplement included in many complementary and alternative medicines marketed for boosting immunity. Allergic reactions to echinacea include severe allergic reactions
(anaphylaxis), acute asthma attacks, severe urticaria (hives), and swelling.

Other adverse reactions to echinacea include:

  • Burning or stinging of the tongue
  • Shivering, fever, and muscle weakness when injected
  • Hepatitis (liver inflammation)
  • Rashes, muscle aches and pains, delayed asthmatic reactions, and stomach upset

© ASCIA 2024

Content updated June 2024

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