Cosmetics contain a number of active agents and ingredients of vehicle. Active agents of cosmetics are known as more common sensitizer. Ingredients of vehicle are weak sensitizer that produce only mild scaly, dry eruption rather than obvious eczematous reaction. Kook have proposed a group of vehicle ingredients which should be tested on patients with allergic conntact dermatitis. The authors applied the vehicle tray patch test, which had been proposed by Kook, on 145 patients with allergic cosmetic dermatitis. The results of patch test are as follows; 1) The patients reactive to more than one ingredients, are 71. 2) Each ingredients show positive reactions in more than 2 patients. 3) The ingredients which give significantly high reactivity are sodium lauly1 sulfate, ethylene diamine, isopropy1 myristate, turpentine, and propylene glycol. The authors conclude that the vehicle tray, which had been proposed by Kook, also can be applied to patients with allergic cosmetic dermatitis.