The comparison of the effect obtained in children with primary acute pyelonephritis treated with lymphotropic ampiox plus lidase against oral or intramuscular ampiox showed more rapid induction of clinical remission and more pronounced tendency to normalization of immunological indices in the patients on lymphotropic ampiox. In addition, the lymphotropic route made it possible to decrease the drug dose and number of its injections which is of importance in pediatric practice. The above advantages say in favour of wide application of indirect lymphotropic therapy for pyelonephritis in children.