Thaumatin is a sweetener and flavor modifier commonly used in the food industry. Likewise, gum arabic is widely used as a food stabilizer and thickening agent. We report here that a powder mixture composed of 10% thaumatin and 90% gum arabic led to allergic symptoms in the upper airways in occupationally exposed individuals: four of eight workers of a chewing gum factory exposed to this powder mixture had pronounced rhinitis. A positive skin prick test result for pure thaumatin was obtained in all four individuals with rhinitis of whom two also had a positive skin prick test result for pure gum arabic and gum arabic-specific IgE. Subsitution of a powdered thaumatin with a liquid form reduced symptoms among the rhinitic workers. Although gum arabic is a well-known potential allergen, we were unable to find prior documentation of allergic symptoms to thaumatin when it is used in the food industry.