The review is dedicated to treatment of allergic diseases in childrenThe prevalence of allergic diseases such as seasonal and persistent allergic rhinitis, urticaria, atopic dermatitis and bronchial asthma has been steadily increasing in recent years. Allergic diseases have a tremendous impact on the quality of patients' life. Common pathogenetic link of development of any form of allergy (true and pseudoallergic) is the release of biologically active substances which leads to the development of one or another symptom complex (depending on the "shock" organ). The most important role in the pathophysiology of allergic diseases belongs to histamine mediator (5[2-aminoethyl]-imidazole) which is primarily contained in mast cells and basophils. The influence of histamine released from the IgE-activated mast cells during the early phase of an allergic reaction on organs and tissues mainly determines acute symptoms of allergic diseases. As a result of development of type I allergic reaction and the IgE-dependent degranulation of mast cells, the elevation of histamine concentration in blood plasma and tissue fluid takes place. The histamine level increase may also be caused by other mechanisms of cell activation: e.g., in the event of pseudoallergic reactions, the mast cell membrane is destroyed not by an antigen-antibody complex, but by some chemical or other agent. Pharmacological action of histamine is mediated through the stimulation of histamine receptors. Currently, four types of histamine receptors are known. Development of allergic reactions is mainly associated with the H1-histamine receptors, the activation of which leads to the contracture of smooth muscles of bronchi and gastrointestinal tract, increased vascular permeability, increased mucus secretion by nasal mucous glands and irritation of nerve endings. Histamine impact on histamine receptors results in the involvement of respiratory tract mucosae in the pathological process and occurrence of symptoms of allergic rhinitis and bronchial asthma, namely, itching, sneezing, swelling of mucosae, mucus hypersecretion and bronchospasm; when the ocular mucosa is affected, symptoms of allergic conjunctivitis take place, namely, itching, redness, swelling, lacrimation. The typical clinical effects of histamine on the skin are itching,