Children below 4 years of age and in public day care were invited to participate in this prospective study. The children started with a visit to an ENT doctor and after inclusion the children started to spray twice daily with glucose oxidase+glucose or only saline+glucose for 3 months. During this period the parents were asked to fill in a home protocol recording upper respiratory tract symptoms as: rhinitis, cough, fever, ear ache. After 6 weeks and 12 weeks the children had scheduled visits to the ENT department, where an ENT doctor examined the throat, nasal cavity and the ear drums for otitis media. After 12 weeks of treatment a nasopharyngeal swab was taken for bacterial culture.