The Effect of Nasal Carbon Dioxide (CO2) in the Treatment of Seasonal Allergic Rhinitis

Inclusion Criteria: * Able to read and understand informed consent and voluntarily consent to sign the informed consent form * Able to comply with the requirements of the protocol (e.g., complete the diary within the protocol-specified window) * Minimal 2-year history of Fall seasonal allergic rhinitis requiring pharmacotherapy * Positive skin test to one or more Fall seasonal allergen (e.g., ragweed, birch pollen, etc.) * Females of childbearing potential must commit to using an acceptable method of birth control and have a negative pregnancy test Exclusion Criteria: * History of asthma (other than mild intermittent) * Acute or significant sinusitis or upper respiratory infection within 14 days of enrollment * Existing serious medical condition (e.g., severe emphysema) that precludes participation * Females who are pregnant or breast-feeding and/or who plan to become pregnant or to breast-feed during the study participation or within 7 days after the last study drug administration * Initiation of immunotherapy or have a change in immunotherapy dose within the 6 months preceding enrollment (if on immunotherapy, the same dose must be maintained throughout the trial) * Planned travel outside the study area for the duration of study period * Participation in another clinical study within 30 days of planned enrollment date and for the duration of the study * Participation in a previous study with Nasal CO2