The frequency of food-induced anaphylactic shocks (FIAS) has been investigated beside 46 emergency departments, 29 departments of Dermatology, and 19 departments of Intern Medicine or Pneumology. 794 A.S. have been reported. FIAS represent 10.2% of the etiologies. More than a third of them are relapsing anaphylaxis. Food allergy had been previously identified in 23.4% of cases. The allergen was present as a hidden allergen or inadvertently consumed in 30.8% of FIAS. 9.9% of the patients were asthmatic. An enhancing factor was heightened in 25.9% of cases: alcohol, exercise, simultaneous intake of aspirin, beta-blockers, conversion enzyme inhibitors. Other factors predisposing to food anaphylaxis were a cross-reactivity shared by pollens and fruit, latex and exotic fruit, house dust mites and snails, or mastocytosis. More than 15 allergens were detected: egg (11.6%), fish (10.4%), crustaceans (10.4%), milk (6.5%), fruit-latex group (6.5%), peanut and other leguminosae (soy, peas, lentils, guar gum...), celery, garlic, etc... The food allergen still remained unknown in 25% of cases. However, the rate of efficiency of the diagnosis reached 94% in the Allergy Units. In addition 10.2% of A.S. were considered idiopathic, raising the hypothesis of allergy to masked food allergens. Compared to a previous study from the 1982's, this survey shows a striking increased prevalence of FIAS.(ABSTRACT TRUNCATED AT 250 WORDS)