A 69-year-old nurse was evaluated for a recent episode of anaphylaxis that had occurred after psyllium ingestion. She had experienced recurrent rhinitis and asthma related to psyllium exposure for the past 15 years. The diagnosis of psyllium hypersensitivity was established by a positive psyllium puncture skin test, an elevated psyllium-specific IgE level in serum, and a confirmatory soluble-antigen competitive inhibition test. The patient was symptomatic for several years, and this diagnosis was not considered until she suffered potentially life-threatening anaphylaxis. Psyllium hypersensitivity may be a more common phenomenon than is currently appreciated by physicians and other health-care providers.