ObjectiveTo systematically review the efficacy of pidotimod in children.MethodsPubMed, The Cochrane Library, EMbase, CNKI, CBM, VIP and WanFang Data databases were searched online to collect randomized controlled trials (RCTs) on pidotimod in children from inception to January, 2018. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies, then, meta-analysis was performed by using RevMan 5.3 software.ResultsA total of 310 RCTs involving 30 525 children were included. The results of meta-analysis showed that, compared with conventional therapy, conventional therapy combined with pidotimod could not improve the efficacy of children with respiratory infections (RR=1.78, 95%CI 0.99 to 3.20, P>0.05). However, pidotimod could significantly reduce the number of respiratory tract infection (MD=−2.79, 95%CI −3.12 to −2.46, P<0.05), shorten the time of respiratory tract infection (MD=−4.15, 95%CI −4.72 to −3.58, P<0.05), and the time of fever (MD=−1.47, 95%CI −1.77 to −1.17, P<0.05) in recurrent respiratory tract infection. Pidotimod could also reduce the time of fever (MD=−0.90, 95%CI −1.60 to −0.20, P<0.05) in children with mycoplasma pneumoniae pneumonia, the time of fever (MD=−1.51, 95%CI −1.91 to −1.11, P<0.05) in children with hand-foot-mouth disease, and reduce the incidence of anaphylactoid purpura followed up for 6 months (RR=0.42, 95%CI 0.30 to 0.61, P<0.05) in children with anaphylactoid purpura. However, there was no significant difference between two groups in the recurrence of asthma for 1 year follow-up (RR=0.80, 95%CI 0.60 to 1.06, P>0.05).ConclusionCurrent evidence shows that pidotimod may be effective for children with respiratory tract infection, asthma, hand-foot-mouth disease, could reduce disease relapse and relieve symptoms related to illness.