13 patients allergic to the cationic emulsifier oleamidopropyl dimethylamine were tested with a series of related amide-amine type surfactants in order to investigate its cross-reaction pattern. With 1 exception, all patients reacted to at least 4 of the test materials. Most reactions were observed to ricinoleamidopropyl dimethylamine lactate and tallowamidopropyl dimethylamine (11 patients, 85%); 9 patients (of 12 tested, 75%) reacted to lauramidopropyl dimethylamine and 6 (46%) to myristamidopropyl dimethylamine. A certain pattern of cross-reactivity was recognised.