The use of maoto (Ma-Huang-Tang), a traditional Japanese Kampo medicine, to alleviate flu symptoms: a systematic review and meta-analysis.

Influenza is a common viral infection worldwide. Maoto (ma-huang-tang) was developed in ancient China and is used to alleviate flu symptoms. Currently, no meta-analyses have evaluated the efficacy and safety of maoto for alleviating flu symptoms.In the present study, we searched MEDLINE/PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE, a Japanese database (Ichushi), two Chinese databases (China National Knowledge Infrastructure and VIP), and two Korean databases (Korean Medical database and Korean Association of Medical Journal Editors) for studies published in or before October 2017. Clinical studies that compared maoto plus neuraminidase inhibitors (NAIs) vs. NAIs alone, or maoto alone vs. NAIs alone, were included in the present analysis. The primary outcome measure (efficacy) was the length of time from the start of medication to resolution of influenza symptoms (fever, headache, malaise, myalgia, and chills) and virus isolation. The secondary outcome measures (safety) were as follows: (1) side effects and adverse reactions, such as nausea, abnormal behaviour, or discontinuation of symptomatic treatment; (2) morbidity (complications caused by influenza infection) or mortality; and (3) hospitalisation for any reason.Twelve relevant studies were identified, including two randomised controlled trials (RCTs, N = 60) and ten non-randomised studies (NRSs, N = 1110). We found that maoto plus NAIs was superior to NAIs alone in terms of the duration of fever in one RCT (P < 0.05, median difference = - 6 h) and four NRSs (P = 0.003, weighted mean difference = - 5.34 h). The duration of symptoms or virus isolation did not differ between maoto and NAIs. No severe side effects or adverse reactions were reported related to maoto or NAIs.Although we could not reach a definitive conclusion because of the small sample sizes and high risk of bias in the analysed studies, maoto may lower the duration of fever when it is used alone or in combination with NAIs and may be a well-tolerated treatment. More RCTs are needed to determine the efficacy and safety of maoto.