Common Ragweed
Allergy Facts, Symptoms, and Treatment

Featuring lacy leaves and growing to a height of roughly 1 meter (3.5 feet), common ragweed is known by a multitude of names, including Roman wormwood, hogweed, hogbrake, bitterweed, annual ragweed, blackweed, carrot weed, hayfever weed, hayweed, stammerwort, and wild tansy.1,2,3 While native to North and Central America, common ragweed is an annual herb that has been widely distributed across the world, where it's found in disturbed locales such as construction sites as well as amid cultivated land and riverbanks.3 Common ragweed plants create enormous amounts of pollen, as a single plant is capable of producing millions of small pollen grains, which often travel long distances.4 Released spring to fall, the wind-borne pollen is highly allergenic and can induce allergic rhinitis (hay fever) and dermatitis.1,3,5 In fact, 10 percent of the United States population is ragweed sensitive according to a large skin test survey.4

Where is common ragweed found?

Although it's native to North and Central America, common ragweed is widely distributed across the world, including Africa, Asia, Australia, and Europe. It's typically found in disturbed sites including construction sites, railways, and cultivated and uncultivated cropland. Plus, it naturally occurs along riverbanks, in grasslands, and in dry meadows.3

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Are there other allergens I could be sensitized to?*

Many patients with common ragweed allergy can experience symptoms when exposed to other allergens such as tree, weed, or grass pollens, making it difficult to determine which pollen is causing the symptoms, especially when pollen seasons are overlapping. This is called cross-reactivity and occurs when your body's immune system identifies the proteins, or components, in different substances as being structurally similar or biologically related, thus triggering a response.7 Other respiratory allergens that may cause reactions associated with common ragweed are certain grasses, trees, and weeds (e.g., birch, alder, juniper, mugwort, olive, goosefoot, etc.).7

If you experience an itchy mouth or throat after eating fresh fruit or raw vegetables, you may suffer from Oral Allergy Syndrome (OAS), sometimes called Pollen Food Allergy Syndrome (PFAS). This condition is caused by your immune system's reaction to similar proteins, or components, found in different allergens. It is quite common, with up to 25 percent of children with allergic rhinitis (i.e., hay fever) also suffering from OAS.8 Common plant foods involved in OAS for common ragweed include melon, soybean, watermelon, citrus, banana, pineapple, persimmon, zucchini, tomato, hazelnut, peanut, corn, and many more.7

Knowing the proteins, or components, within each allergen that are triggering your symptoms can help guide your management plan. With that in mind, and based on your symptom history, your healthcare provider may suggest something called a specific IgE component test, which can help reveal other pollens and foods you may react to. Results from this test can also help your healthcare provider decide if allergen immunotherapy may reduce your symptoms.7

Already have your specific IgE component test results?

Your component test results will include the name of the components (a series of letters and numbers). Your healthcare provider will likely review the results with you, but here you'll find an at-a-glance breakdown you can use as a reference. Simply match the component names to the list below to see what they mean in terms of symptom management.7

nAmb a 1  

  • Indicates that symptoms may be caused by ragweed pollen or mugwort pollen.7
  • Ragweed pollen immunotherapy may be considered.7

rPhl p 7

  • Indicates symptoms may be caused by grass or by other pollen, e.g., from trees, grass, and weeds. Further investigation may be considered to confirm all allergy triggers.7
  • May be associated with more severe symptoms and higher prevalence of asthma than other grass pollen allergies.7

rPhl p 12

  • Indicates that symptoms may be caused by grass or by other pollen, e.g., from trees, grass, and weeds.7
  • May be associated with PFAS after ingestion of fruit and vegetables such as melon, tomato, apple, and celery. Further examination may be considered.7


  • Positive specific IgE for ragweed in combination with MUXF3 CCD (Cross-Reactive Carbohydrate Determinant) being the only positive component test indicates that the cause of symptoms may be something other than ragweed pollen.7

Test results should be interpreted by your healthcare provider in the context of your clinical history. Final diagnosis and decision on further management is made by your healthcare provider.

*These products may not be approved for clinical use in your country. Please work with your healthcare provider to understand availability.

How do I manage my allergy?

The management of allergic rhinitis includes avoidance of relevant allergens, symptomatic treatment, and allergen immunotherapy.8-10

  • Check local pollen counts daily and limit time outside when pollen counts are high. Rain helps clear pollen from the air, so the best time to go outside is after a good rain.
  • Delegate outdoor chores whenever possible and wear a pollen mask if you must do outside tasks. 
  • Keep windows closed and use air conditioning instead.
  • Wash bedding at least once a week in hot, soapy water.
  • Wash your clothes after outdoor activities and dry all clothes in a dryer as opposed to line drying outdoors.
  • Bathe and wash your hair every day before bedtime to keep pollen out of your bed.
  • Wipe off any pets to remove pollen before letting them into your home.
  • Ensure everyone removes their shoes before entering your home.
  • Use certified asthma and allergy air filters.
  • Pharmacological treatment, including antihistamines, corticosteroids, decongestants, and saline douches.
  • Allergen immunotherapy as directed by your healthcare provider.

Looking for more allergy info and management tips?

Visit the Living with Allergies section

Common Symptoms

Common ragweed allergy symptoms can be similar to many other pollen allergies and may include:3,6,8

  • Sneezing
  • Nasal congestion
  • Runny nose
  • Watery eyes
  • Itchy throat and eyes
  • Wheezing

If you're sensitized to common ragweed and have asthma, the weed pollen may trigger or worsen asthma symptoms, such as coughing and wheezing.6

How do I know if I'm allergic?*

Together with your symptom history, skin-prick testing or specific IgE blood testing can help determine if you are sensitized to a particular allergen. If you are diagnosed with an allergy, your healthcare provider will work with you to create a management plan.

*These products may not be approved for clinical use in your country. Please work with your healthcare provider to understand availability.

Pollen Season

While common ragweed pollen is shed from spring to fall, it's released in great abundance in late summer.1,2

  1. [Internet]. Plymouth Meeting, PA: IQVIA Inc.; 2020. Available from:
  2. Encyclopedia Britannica [Internet]. Chicago: Encyclopedia Britannica Inc.; 2018 Jan 29. Available from:
  3. Iamonico D. CABI Invasive Species Compendium.|place unknown|:CABI, 2016 Nov 6. Available from:
  4. D'Amato, G., Cecchi, L., Bonini, S., Nunes, C., Annesi-Maesano, I., Behrendt, H., Liccardi, G., Popov, T. and Van Cauwenberge, P. (2007), Allergenic pollen and pollen allergy in Europe. Allergy, 62: 976-990. doi:10.1111/j.1398-9995.2007.01393.x.
  5. [Internet]. |place unknown| Medizinische Universitat Wien. 2020. Available from: Available from:
  6. American College of Allergy, Asthma & Immunology [Internet]. Arlington Heights, IL: American College of Allergy, Asthma & Immunology; 2014 [2018 Apr 23]. Available from:
  7. EAACI, et al. Molecular allergology user's guide. Pediatr Allergy Immunol. 2016 May;27 Suppl 23:1-250. doi: 10.1111/pai.12563. PMID: 27288833. Available from:
  8. Roberts, G., Xatzipsalti, M., Borrego, L., Custovic, A., Halken, S., Hellings, P., Papadopoulos, N., Rotiroti, G., Scadding, G., Timmermans, F., Valovirta, E. Paediatric rhinitis: Position paper of the European Academy of Allergy and Clinical Immunology. Allergy. 2013 Sep;68(9):1102-16.
  9. Asthma and Allergy Foundation of America [Internet]. Arlington, VA: Asthma and Allergy Foundation of America; 2019 Apr 9. Available from:
  10. Mayo Clinic [Internet]. Rochester, MN: Mayo Foundation for Medical Education and Research; 2020 Apr 16. Available from: