This article addresses the observational findings of the first systematic study undertaken by a manufacturer to address the impact of allergies and use of allergy medications on health, safety, and productivity. It provides background for 3 other papers from the same project, including an evaluation of an intervention to promote appropriate medication use among affected employees, which appear in this issue. The observational data are developed on 10,714 employees from: 1) 2 employee surveys; 2) administrative databases monitoring employee absenteeism, workers compensation, short-term disability, and group health. The results show that health, productivity, absenteeism, workplace injury, and workers compensation measures register consistent declines as allergy severity levels increase. This pattern is present but less pronounced for the short-term disability and group health measures. In addition, among the 16 measures registering a significant allergy burden, 6 posted significant advantages for the use of nonsedating antihistamines relative to other medication regimens that included sedative antihistamines. These results document the burden of allergies and the capacity of medications to reduce this burden. Effective intervention programs that target this condition can achieve improved health, productivity, and related outcomes.