We describe 5 observations of cutaneous reactions or immediate hypersensitivity with different hypoglycemic sulfonylurea: Quincke's oedema with glibornuride, three urticaria (one was followed by bronchospasm and collapsus) with glibenclamide, one bullous dermatitis with carbutamide. With special regard to cross reactions between sulfonylurea: we observe the tolerance of glipizide after glibenclamide induced urticaria, tolerance of glicalazide after glibornuride induced Quincke's oedema and eruption, tolerance of glibornuride after chlorporpamide induced urticaria and Quincke's oedema. In the literature, cross reactions between 1st generation sulfonylurea are noted, but not cross reactions between 1st and 2nd generation.