The role of glucan in stimulation of immune reactions has been studied for decades. In this report we focused on the effects of orally administered glucan in children with chronic respiratory problems. We measured the physical endurance using a 6MWT test and the levels of eNO in 50 children aged 8-12 years and evaluated the effects of 100 mg/d oral dose of glucan. We found significant improvements in physical indurance and exhaled nitric oxide in glucan-treated children. In addition, strong improvements in general conditions were found. Short-term oral application of natural immunomodulator ?-glucan enhancers the overall health and regulation of energetic metabolism in children with chronic respiratory problems.