THE AIM of the study was an attempt to determine the correlation between the incidence of IgE - dependent allergy and the severity of gastro-oesophageal reflux in children and youth. PATIENTS AND METHODS: 222 patients aged from 1 to 16 years with diagnosed acidic gastro-oesophageal reflux on the basis of all day ph observations were enrolled to the study. IgE - dependent allergy was diagnosed on the basis of the history, physical examination, evaluation of cIgE concentration in serum and the results of skin tests with chosen food and pollen allergens. RESULTS: IgE - dependent allergy was found in 48% of patients with gastro-oesophageal reflux. In analysis of main parameters of ph examination (percent of time in which ph was lower than 4.0 and the quantity of refluxes lasting over 5 min) in the group of patients with symptoms of IgE - dependent allergy there was a statistically significant higher incidence rate of considerable gastro-oesophageal reflux and lower incidence rate of small gastro-oesophageal reflux in comparison with patients without symptoms of allergy. It was also determined that in this group the oesophageal mucosa in patients with gastro-oesophageal reflux and IgE dependent allergy was statistically significant more subjected to harmful influence of acidic gastric contents in comparison to the group of patients with isolated gastro-oesophageal reflux. CONCLUSIONS: IgE - dependent allergy and coexistent gastro-oesophageal reflux in children and youth escalate the intensity of gastro-oesophageal reflux and more often oesophageal mucosa is subjected to harmful influence of gastric contents.