Eleven patients with cold urticaria and six controls were studied by a forearm dermal perfusion technique for the presence of kinins and histamine. After application of ice, kinins were demonstrated in all the cold urticaria patients upon urtication and in none of the controls. Histamine was not demonstrated in the patients after urtication but was found after subcutaneous injection of compound 48/80, a histamine liberator, into the urtication site. Histamine was not present in the controls. Kinin activity was abolished in the patients by subcutaneous injection of epinephrine into the wheal. Acetylsalicylic acid (aspirin) (19.5 mg/100 ml of blood) had no effect on the kinin production in one patient. Quantitative histamine content of the skin did not differ in the patient group and the control group; however, both groups had decreased histamine content after cold exposure.