Reynoutria japonica Houtt for Acute Respiratory Tract Infections in Adults and Children: A Systematic Review

Systematic review of 8 randomized controlled trials including 1,123 participants with acute respiratory tract infections. Studies were conducted in China in inpatient and outpatient settings and included mostly pediatric upper respiratory tract infections plus two adult acute exacerbation COPD trials. All active arms used Reynoutria japonica as part of multi-herb formulas rather than as monotherapy.

Across eight Chinese randomized trials, the active interventions were Reynoutria japonica-containing multi-herb formulas, most commonly Shufeng Jiedu Capsule (SFJDC), and also Tuire Liquid and Xuanfei Quyu Tongluo Liquid. Treatment duration ranged from 3 to 45 days, but specific doses, frequencies, and routes were not reported. No monotherapy trials of Reynoutria japonica were identified.

Herbal remedies containing Reynoutria japonica were associated with better symptom relief, but the evidence was very low quality. Symptom improvement rate favored the intervention across 7 trials and 1,013 participants (RR 1.14, 95% CI 1.09 to 1.20; I2 = 0%; p < 0.00001). Fever duration and Murray lung injury score were reduced in some comparisons. Adverse events did not differ significantly overall across 5 trials and 676 participants (RR 0.33, 95% CI 0.11 to 1.00; I2 = 0%; p = 0.05).

Overall certainty was very low because the included trials had poor methods and incomplete reporting. The evidence base was small, heterogeneous in formulas and populations, and entirely from China. No monotherapy trials were available, and dosing details were inconsistently reported.