In recent years, there have been reports that glutamine support improves immune functions in adult patients with malignancy, but there is a lack of data in children. Oral glutamine support of 4 g/m(2)/day was given to 21 children with various solid tumors, aged 1-17 years (9.86 +/- 5.38) for all 5 days of a chemotherapy course. The same parameters in another course of the same protocol without glutamine supplementation were considered as controls. There were significant improvements of some nutritional and immunological parameters in the glutamine-supplemented course. Also glutamine seemed to reduce antibiotic necessity. Oral glutamine supplementation could be considered in children with solid tumors receiving chemotherapy.