Over the past few decades we are witnessing a steady increase of the prevalence of allergic diseases. Nowadays, this group of diseases constitutes a significant economic burden for the healthcare system of developed countries, both in the terms of direct treatment costs and social costs associated with absenteeism and disability pensions. Studies indicate that this might be associated with unfavourable influence of the environment and faulty behaviour leading to change of life- style, both leading to the development of allergies. This paper presents health hazards associated with these diseases in the context of public health and most frequently quoted causes of increasing incidence of atopic diseases. The authors present a short analysis of the key epidemiological studies of the last decades. The increasing incidence of asthma, allergic rhinitis and anaphylaxis is analysed, with special emphasis on drug reactions. Data originate from studies performed in many letcountries worldwide and refer to both adults and children. In the Midspan family study carried out in Scotland, a threefold increase in the prevalence of asthma and pollinosis has been noted over a period of twenty years of observation. Similar results were obtained in a study of schoolchildren in Sydney, where a fourfold increase in the incidence of asthma and pollinosis was noticed. A twofold increase in the incidence of these diseases has been notices in Israel in the '90 and a similar trend was observed in China. An additional finding of the Chinese study was that the prevalence of asthma was higher in highly urbanized areas. There was a correlation between the risk of asthma and some everyday activities (e. g.: the use of gas ovens for cooking, high humidity in living areas, the use of pillows made of synthetic fabrics). On the other hand, the use of cotton bedclothes and high intake of fruits and vegetables had a protective effect.