The national burden of food-related acute allergic reactions treated in the emergency department (ED) was described using data from 2 large ED-based cohort studies (a multicentre retrospective cohort study at 21 North American EDs and a multicentre retrospective cohort study performed at 3 Boston EDs) and the National Hospital Ambulatory Medical Care Survey in the USA. Overall, from 2001 to 2005, a total of 7 075 000 ED visits were identified by using the specified ICD-9-CM codes, of which an estimated 1 015 000 visits (14%) were considered to be true food-related acute allergic reactions. Among the 1 015 000 ED visits for food-related allergic reactions from 2001 to 2005, an estimated 448 000 visits (44%), or 90 000 visits each year, would be classified as probable anaphylaxis. On average, an ED visit caused by food-related anaphylaxis occurred somewhere in the USA every 6 minutes. These estimates are for number of ED visits and include repeat visits; they are not numbers of unique patients with food allergy. These results suggest that the number of US ED visits for food-related acute allergic reactions may be significantly higher than estimated in previous reports.