Five nurses aged 31–55 years old had a history of asthmatic symptoms after being exposed to psyllium that they prepared and distributed to patients. They had been nurses for 9–20 years and had reported asthmatic symptoms related to work in the past 3–12 months. They reported symptoms of rhinoconjunctivitis and all were atopic but only one had a previous history of asthma. Four of the five tested subjects had an immediate skin reaction to a commercial psyllium extract. All had IgE antibodies to psyllium. At the time that they were investigated, four out of the five had a significant increase in bronchial responsiveness to methacholine (PC 20 <8 mg/ml). Inhalation challenges with psyllium caused isolated immediate (one subject) and dual reactions (three subjects). One subject exposed for only 1 min to the psyllium powder experienced a severe immediate bronchospastic reaction, which required intubation for 3 h with complete functional recovery thereafter. This experience illustrates the precautions necessary, with the inclusion of a cautious dose-response approach, even with an‘occupation-type’challenge in the laboratory.