A study of cosmetic intolerance has been undertaken in 5202 patients tested for possible contact dermatitis. Each patient has been evaluated by medical history and patch testing. Intolerance to cosmetics involved only 5.9% of the total population tested. If other possible sources of allergens (medication, occupation, hobbies etc) are associated, this figure rises to 11.7%. The origin of the cosmetic intolerance is more often an allergy than irritation. Soaps and shampoos are the most important types of cosmetics responsible for adverse reactions. The principal allergens are the fragrances, preservatives, hair dyes and the patients' own products. In this last category, the specific allergen has not always been detected.