Symptom data and spirometry data were collected before and after 1 h of beach exposure. Subjects kept daily symptom diaries and measured their peak flow each morning for 5 days following beach exposure. During non-exposure periods, there were no significant changes in symptoms or pulmonary function either acutely or over 5 days of follow-up. After the beach exposure during an active Florida red tide, subjects had elevated mean symptoms which did not return to the pre-exposure baseline for at least 4 days. The peak flow measurements decreased after the initial beach exposure, decreased further within 24 h, and continued to be suppressed even after 5 days. Asthmatics may continue to have increased symptoms and delayed respiratory function suppression for several days after 1 h of exposure to the Florida red tide toxin aerosols.