Although the ideal treatment for urticaria is identification and removal of its cause, no underlying cause can be discerned in the majority of instances. The chief clinical problem is the treatment of chronic idiopathic urticaria. H1-receptor antagonists are the major class of therapeutic agents used in the management of chronic idiopathic urticaria. The H1 antagonists have been divided into subgroups based on their chemical structure. The second-generation H1 antagonists now available are particularly advantageous for individuals who must remain alert while working. Terbutaline, a beta-adrenergic agonist, is of occasional benefit as an adjunct therapy in combination with an H1 antagonist. The oral administration of disodium cromoglycate is ineffective in patients with chronic idiopathic urticaria, although a few individuals with urticaria caused by food allergy may respond to this drug. It is best to avoid repeated injections of epinephrine and the systemic administration of corticosteroids. Urticaria has a capricious course: it may respond to the administration of placebos or it may resolve spontaneously. About 50% of the patients with urticaria are free of lesions within 1 year, but 20% continue to have episodes for more than 20 years.