Safety and effectiveness of ginger for acute respiratory infections: A systematic review of randomized controlled clinical trials

Abstract

Introduction: The development of antibiotics is one of the greatest breakthroughs in modern medicine. However, antimicrobial resistance (AMR) is exacerbated by excessive use of antibiotics, including in the treatment of upper respiratory tract infections (URTIs) . It is estimated that over 1 million deaths each year are attributable to bacterial AMR, and this could increase to 10 million by 2050. The search for novel alternatives to antibiotic therapies focuses on natural compounds from plants like ginger, which is widely used and believed to be effective for treating respiratory tract infections. Constituents of ginger have demonstrated antiviral, antimicrobial and anti-inflammatory properties. The aim of this systematic review is to evaluate the clinical effectiveness and safety of ginger as a single herb in randomized controlled trials (RCTs) for treating acute respiratory infections (ARIs). Methodology: The protocol was registered on PROSPERO (CRD42024562098). We searched six electronic databases - PubMed, EMBASE, Cochrane library, CINAHL, AMED and CNKI from inception to 27th February- 2nd October 2024. Data from this search was exported to Rayyan for screening. We included RCTs of ginger mono-herbal oral therapies in patients with diagnosis or symptoms of ARIs (including COVID-19) and compared with usual care, placebo or other interventions. The Cochrane risk-of-bias tool for randomized trials (RoB-2) was used to assess risk of bias. Result: A total of 10, 281 titles were screened in Rayyan. The screening yielded only one eligible RCT, with 227 adult participants who tested positive for COVID-19, were asymptomatic and quarantined in shelter hospitals in China. Ginger powder (1.5 g twice daily in warm water), in addition to standard care, reduced quarantine duration (time to negative Polymerase Chain Reaction (PCR) result, without major symptoms) by 2.4 days (95 % CI 1.6 – 3.2), compared to usual care alone. The effects seemed to be greater for participants aged 60 years or older, men, and those with pre-existing medical conditions. No data on adverse events were reported. The study was at high risk of bias due to concerns about randomisation and lack of blinding. Conclusion: More high-quality randomized controlled clinical trials are needed to assess the efficacy of ginger for the treatment of ARIs.