If your nose starts running soon after the tree goes up, mold may be the reason. A study by pediatricians at SUNY Upstate Medical University found that clippings from real Christmas trees carried a variety of molds, most of them potential allergens. Artificial trees aren’t automatically better: stored poorly, they can bring mold and dust into your home too.
This guide explains the triggers, how to prepare a real or artificial tree, and simple ways to keep holiday sniffles down. For more, see our mold and humidity guides.
Jump to: Quick answer · What triggers symptoms · Real tree tips · Artificial tree tips · Indoor steps · FAQ
Quick answer
- Mold is the main suspect. Real trees carry molds that can be released indoors.
- Not everyone reacts: the study’s lead researcher said that if you and your children don’t have obvious allergies, it probably won’t bother you.
- Rinse a real tree with a garden hose and let it dry before bringing it in, or ask the lot if they offer tree washing.
- Keep it up for a shorter time: there’s some evidence the longer and warmer the tree is indoors, the more spores it releases.
- Store artificial trees well and clean them before setup, since they can collect mold and dust.
What triggers Christmas tree allergies
| Trigger | Where it comes from | What helps |
|---|---|---|
| Mold | Grows on bark and needles of real trees; can grow on artificial trees stored in damp places | Rinse and dry real trees; store artificial trees dry and clean them before use |
| Dust | Collects on artificial trees and decorations in storage | Wipe down the tree and ornaments, ideally outdoors or by someone without allergies |
| Outdoor debris | Dirt and plant material on a fresh-cut tree | Shake and rinse the tree outside before bringing it in |
The Upstate study, published in Annals of Allergy, Asthma and Immunology, noted that the molds it identified are potential allergens that have been shown to increase the risk of wheeze, persistent cough and allergic sensitization in infants. The researchers suggested tree molds may contribute to the rise in respiratory illness around the holidays.
Tips for a real tree
- Ask the tree lot whether it offers tree washing.
- Rinse it yourself with a garden hose and let it dry fully before bringing it inside.
- Shake it outdoors to remove loose needles and debris.
- Limit the time indoors. Put the tree up closer to the holiday and take it down soon after.
- Wear gloves when handling it if sap or needles irritate your skin.
Tips for an artificial tree
- Store it dry in a sealed bag or container, not in a damp basement or garage.
- Clean it before setup, outdoors if possible, to remove dust and any mold.
- Clean ornaments and decorations too; they sit in storage all year.
- Let someone without allergies do the unpacking and wiping if you can.
Keep indoor air in check
- Use an air purifier with a HEPA filter in the room with the tree, as the Upstate researchers suggested. See air purifier myths for sizing tips.
- Keep humidity in check. The EPA recommends keeping indoor humidity below 60%, ideally 30% to 50%, to discourage mold; see humidity control for allergies.
- Vacuum fallen needles with a HEPA vacuum.
- Watch for other holiday triggers, such as scented candles, fireplace smoke and dust from decorations. See common holiday allergies and fragrance allergy.
If symptoms persist, an allergist can test whether mold or something else is the cause. Winter dust mite and pet dander exposure can also rise as you spend more time indoors; see do seasons affect allergies?
This guide is general information, not medical advice. Read our medical disclaimer.
Frequently asked questions
Can you be allergic to a Christmas tree?
Usually the problem is mold or dust on the tree rather than the tree itself. A study of real Christmas tree clippings found a variety of molds, most of them potential allergens.
Are artificial Christmas trees better for allergies?
They avoid fresh-tree mold, but if stored improperly they can collect mold and dust. Store them dry and clean them before setup.
How do I get mold off a real Christmas tree?
Spray it with a garden hose and let it dry before bringing it inside, or ask the lot whether it offers tree washing.
How long should I keep a real tree up if I have allergies?
Shorter is better. The Upstate researchers noted some evidence that the longer and warmer the tree is indoors, the more spores it releases.
What is Christmas tree syndrome?
It’s an informal name for allergy-like symptoms that start after bringing a tree indoors, often linked to mold.
Sources
- SUNY Upstate Medical University. Christmas trees may harbor unwanted presence, study says. December 16, 2011.
- U.S. Environmental Protection Agency. A brief guide to mold, moisture and your home. Updated February 18, 2026.
Last reviewed: October 21, 2026.
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