The purpose of this study is to evaluate the effect of nasal CO2 on nasal congestion and other symptoms related to Perennial Allergic Rhinitis.

A randomized study to evaluated the safety and effect of nasal carbon dioxide on nasal congestion using acoustic rhinometry in subjects with perennial allergic rhinitis. The acoustic rhinometry is an instrument that will be used to assess the levels of the nasal congestion in each subject. Approximately 20 men and women ages 19-65 years old who have a history consistent with perennial allergic rhinitis requiring pharmacology for at least 2 years and meet all other eligibility criteria will be enrolled in this study. There will be six (6) visits to the clinic. There will be a screening visit, four (4) treatment visits, and an end of study visit. A subject's participation in the study may last up to 58 days. There will be four different doses given in this study. Each subject will receive 3 different doses of the study drug and one dose of the placebo.

Inclusion Criteria:

• Have a history consistent with minimal 2 year history of perennial allergic rhinitis requiring pharmacotherapy.
• Positive skin test to perennial allergens (e.g. cats, dogs, house dust mite, 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 or intermittent)
• Clinically significant nasal disorders
• Acute or significant sinusitis or upper respiratory infection within 14 days of randomization
• Have an existing serious medical condition (such as severe emphysema, other respiratory diseases, heart disease, etc.) that precludes participation in the study
• Use of certain medication s prior to randomization and during study participation
• Participation in prior study with Nasal CO2
• Participation in another clinical study within 30 days of planned randomization date and for the duration of the study