UNLABELLED: Lactose stimulates proliferation and colonization of acidophilic bacteria, which due to fermentation processes lower colonic pH and simplified absorption of some microelements from the intestine. However, the common problem in children is intolerance of this carbohydrate. Treatment, quite simple, is based on partial or total elimination of lactose from diet. Some substitutional products with equivalent nutritional value should be introduced to prevent deficiencies symptoms during lactose-free diet. THE AIM OF THIS STUDY: Determination of milk and dairy products consumption and their connection with lactose malabsorption or lactose intolerance in children above 5 years of age in selected disorders of the alimentary tract: food allergy, celiac disease, secondary enteropathy, functional dyspepsia, irritable bowel syndrome and deficiency of body weight and height. MATERIAL AND METHODS: The number of 301 patients above 5 years of age (135 boys and 166 girls; mean age 11.5 years) were included into the study. Milk and dairy products consumption habits, lactose intolerance symptoms, hydrogen breath test, activity of lactase and villous atrophy were investigated. RESULTS: Decreased sweet milk consumption from, 33.33% in children with food allergy to 55.38% in children with functional indigestion was observed, in spite of gastrointestinal complaints after ingestion of milk. The biggest lactose malabsorption and lactose intolerance frequency was observed in children with decreased sweet milk consumption due to complaints after ingestion of milk and in children who didn't drink milk. There were no statistically significant difference between frequency of lactose malabsorption and lactose intolerance symptoms in children with different dairy products consumption habits. There were no statistically significant difference between frequency of hypolactasia in children with different sweet milk or dairy products consumption habits. CONCLUSIONS: Frequent (33-55%) decreased sweet milk consumption in children in spite of clinical symptoms after ingestion of milk was observed. The biggest lactose malabsorption and lactose intolerance symptoms frequency was observed in children who didn't drink milk and in children with decreased consumption of sweet milk due to complaints after ingestion of milk. There were no statistically significant difference between frequency of lactose malabsorption and lactose intolerance in children with different dairy products consumption habits.