The activity of pidotimod ((R)-3-[(S)-(5-oxo-2-pyrrolidinyl) carbonyl]-thiazolidine-4-carboxylic acid, PGT/1A, CAS 121808-62-6) was studied vs. placebo in a double-blind, randomized, multicentre trial, involving 60 pediatric patients with recurrent urinary tract infections. Recovery from acute