Ninhydrin is a laboratory chemical used as a reagent in the detection of free amino and carboxyl groups in proteins and peptides. We present the case of a laboratory technician who developed symptoms of rhinitis when handling papers immersed in a solution containing ninhydrin. Prick tests for ninhydrin and ninhydrin RAST were positive. The inhalation provocation test in an exposure chamber gave an immediate nasal response. A positive prick test to ninhydrin, an elevated level of specific IgE antibodies to ninhydrin, and the RAST inhibition test confirmed an IgE-mediated type I allergic reaction. We are not aware of any other report of ninhydrin as a cause of IgE-mediated allergy.