Christmas trees and other decorations can trigger allergies in many people, reports the The Atlanta Journal-Constitution.

Tree sap, pollen and terpenes — compounds that give pine trees their scent — can all make allergy sufferers sneeze. But those aren’t the only irritants to look out for.

Live trees can be full of mold. A study last year at SUNY Upstate Medical University found 53 kinds of mold in live Christmas trees, reported. Most of those molds are potential allergens and are known to increase the risk of wheezing, persistent coughing and allergic sensitization in infants.

A 2007 study, the website reported, found that a Christmas tree increases the number of mold spores in an apartment by about six times, and the mold count continued to grow until the tree was taken down.