Ragweed Allergy

Medically Reviewed by Nayana Ambardekar, MD on June 06, 2023
2 min read

If your allergies flare up in the late summer or early fall, you’re probably allergic to ragweed. It’s the most common trigger for hay fever. About 1 out of 5 people get a reaction to it.

Ragweed causes symptoms like stuffy or runny nose, sneezing, and itchy eyes. It can also trigger asthma flares.

People who have ragweed allergies are reacting to its pollen. During ragweed season, one plant can release a billion grains of it into the air.

Ragweed is worse when nights are cool and days are warm and dry.

Its season usually starts in early August and ends in mid-October. Some researchers think climate change may be extending that season.

Everywhere in the U.S. has ragweed. It's most common in the East and Midwest, but it's in every state. Because it's so light, the wind carries ragweed pollen far. Researchers have found ragweed pollen 2 miles up in the atmosphere and 400 miles out at sea.

Avoiding ragweed may be impossible. But there are ways to limit your exposure -- and lower your risk of symptoms.

During ragweed season you should:

Track pollen counts. Check them in the newspaper or on the web. Stay inside when they're high.

Avoid peak ragweed hours. Limit your time outside between 10 a.m. and 3 p.m. Counts are lower in the early morning and late afternoon.

Keep windows closed. At home and in the car, don’t open the windows. Using central air conditioning with a HEPA filter will keep you cool and help filter out pollen.

Change your clothes and wash your hands after you've been outside. Ragweed can stick to skin or clothing.

Watch out for food triggers. Eating foods that contain similar proteins to ragweed pollen proteins can worsen symptoms. Possible triggers are:

  • Bananas
  • Melons
  • Honey
  • Sunflower seeds
  • Chamomile tea

Don't dry laundry outside. It will pick up ragweed pollen. Dry your laundry in a dryer.

Staying away from ragweed may not be enough. You may get help from:

Testing to make sure that you really have a ragweed allergy

Over-the-counter or prescription medications

  • For most people with frequent symptoms, nasal steroids are the best treatment. If your symptoms are more mild, an oral antihistamine may be enough. Both are available over-the-counter.
  • Early treatment. If your doctor says it's OK, start taking medications 2 weeks before ragweed season starts. That way you can stop the allergic reaction before it starts.
  • Allergy shots, which can -- over the course of months or years -- get your body to develop a tolerance to ragweed so it no longer triggers an allergic reaction. Oral tablets placed under the tongue contain the same type of extracts used in allergy shots.