A shot of carbon dioxide to the nose may bring some quick, though short-lived, relief to people with nasal allergies, a preliminary study suggests. So-called intranasal carbon dioxide (CO2) is not yet an approved treatment for nasal allergies. The new study is one of a number of clinical trials being funded by Capnia, Inc., a Palo Alto, California-based company that is developing a hand-held device that -- if approved -- would allow people to administer the CO2 therapy to themselves.
