They are testing carbon dioxide, or CO2, as a way to treat symptoms.
Two small squirts of CO2 - 10 seconds in each nostril - bathes the tissue in a harmless amount of the gas.
"That's it, " says 22-year-old Michael Goad as he completes his treatment in seconds.
Dr. Gary Gross, an allergist at Presbyterian Hospital in Dallas, Texas. "And when that happens, it changes the nerves in your nose so they don't release certain proteins that cause congestion in the nose. So it really will prevent the symptoms of allergic rhinitis."
One spray is supposed to stop sneezing, congestion, and runny nose for hours.
In 3 small studies, the CO2 treatment worked well - and without side effects.
Now, larger tests are underway.
After a week of treatments, Goad says he is waiting for relief to seep in. However, he doesn't know whether he is receiving the actual medication, or a placebo (dummy) treatment.
After getting no relief from any treatment in the past, he is anxious for this to work. "It's easy and pleasant, actually." He says he looks forward to the day he can get on the golf course during ragweed season without a box of tissues.
Allergists are hopeful, because there haven't been any new treatments in years. and the number of people with allergies continues to grow.
The trials are in Phase 2. The final phase could get underway in the next year.