Allergy is a disease of the 20th century. 30% - 40% of the world's population is allergic to various irritants. "Dangerous" agents invading the human body: bacteria, viruses, airborne dust, animal fur, foreign proteins, etc. cause various allergic diseases and can often lead to serious complications (including lethal outcome). This article discusses the causes and characteristic symptoms of allergies, modern methods of diagnosis and treatment with effective and safe antihistamines - Polesin, Lotegra, Loranex, Erius, Eslotin, Telfast, Allerfast, Nixar, Loratadine, Claritine, Cetek, Alertek , Zetrin, Parlazin, Kestin, Zirtek, Terrix, etc. Immunotherapy - or specific hyposensitization - is also characterized as a modern and effective method of treatment, the principle of which lies in the production of specific tolerance (indiscretion) towards the causative allergen.