Kiwifruit allergy is increasing among children but whether heating affects clinical tolerance to kiwifruit is unknown. To assess tolerance to heated kiwifruit in children allergic to fresh kiwifruit. In this prospective trial, 20 children (median age 9.4 yr) with a history of immediate allergic reactions to fresh kiwifruit underwent double-blind placebo-controlled food challenges with steam-cooked (100 degrees C for 5') and industrially homogenised kiwifruit. Skin prick tests with a commercial kiwifruit allergen, raw kiwifruit and double-blind placebo-controlled food challenge with 25 g of fresh kiwifruit were used to confirm the history. Specific kiwifruit IgE to native and homogenized fruit were identified by immunoblotting. Fresh kiwifruit induced positive skin prick wheals in all children (confirmed during challenge in 19 patients). Commercial skin prick test elicited a positive response in five children, steam-cooked kiwifruit in five, and the homogenised kiwifruit preparation in none. UniCAP determinations were positive for kiwifruit in three patients. All children's sera showed specific IgE at immunoblotting with raw kiwifruit and one with the homogenised preparation (major allergens identified: Act c 1 and Act c 2). There was no clinical reactivity following challenge with homogenised kiwifruit but one child reacted to cooked kiwifruit challenge. Industrial heat treatment and homogenisation can make kiwifruit safe for children who are allergic to this increasingly popular fruit. This has dietary implications for children who are allergic to several fruit and vegetable proteins.