Anti-Inflammatory and Cough-Modulating Effects of Plantago lanceolata and Sisymbrium officinale in Upper Airway Infections: A Narrative Review

Acute respiratory infections (ARIs) are among the most common infectious diseases worldwide and represent a substantial clinical and socioeconomic burden. Despite their predominantly viral aetiology, inappropriate antibiotic prescribing remains common, highlighting the need for effective non-antibiotic treatment strategies. In this narrative review, we summarize the pharmacological properties and potential clinical relevance of Plantago lanceolata and Sisymbrium officinale in the symptomatic management of uncomplicated upper airway infections. A narrative literature search of PubMed/MEDLINE, Google Scholar, and the herbal monographs and assessment reports of the European Medicines Agency was conducted, focusing on experimental, clinical, and real-world evidence related to symptom relief, anti-inflammatory effects, and cough modulation. Emphasis was placed on recent in vitro studies investigating epithelial inflammatory responses and cough-related signalling pathways. In cell-based experimental models, both extracts reduced key inflammatory mediators, including prostaglandin E2, tumour necrosis factor-α, and interleukin-6, in human tonsil epithelial cells stimulated with bacterial cell wall components. In addition, both plant extracts attenuated bradykinin-induced intracellular calcium signalling in bronchial epithelial cells, which is consistent with, but does not demonstrate, modulation of cough-related pathways. These in vitro findings provide a biological rationale for their traditional use in relieving sore throat, irritation, and cough, but they are not direct evidence of clinical efficacy, and clinical trials of these two extracts are lacking. Given the central role of symptom burden in driving healthcare utilization and antibiotic-seeking behaviour, effective symptomatic therapies are important. Whether herbal medicinal products with anti-inflammatory and cough-modulating properties improve symptom control and thereby support antimicrobial stewardship remains to be demonstrated. Future research should include randomized controlled trials with validated symptom outcomes and real-world studies evaluating the impact of these extracts on antibiotic prescribing in clinical practice.