Investigation of the Efficacy and Safety of a Syrup Composed of 11 Herbal Medicines in Improving Chronic and Subacute Cough in Patients: A Preclinical Study and a Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Background: Chronic cough is a common health problem that severely affects the quality of life (QOL) in affected individuals. Given the limited efficacy of standard pharmaceutical treatments, there is a growing interest in alternative therapies, especially herbal medicines. Objectives: This study investigated the therapeutic potential of an herbal syrup formulated from a combination of eleven medicinal plants in alleviating chronic cough symptoms. Methods: This study was conducted as a randomized, double-blind, placebo-controlled trial from July 15, 2024, to August 30, 2024. A total of 120 individuals suffering from chronic cough participated in the study. The primary outcome was assessed using the Leicester Cough Questionnaire (LCQ). Results: The administration of the herbal syrup resulted in a statistically significant increase in physical (P-value < 0.001), social (P-value = 0.018), and psychological (P-value = 0.003) scores when compared to the placebo group, as measured ten days after stopping the treatment. Furthermore, the findings demonstrated a significant decline in sputum production, fatigue occurrence, frequency of coughing episodes, hoarseness incidence, and improved overall life satisfaction and sleep quality, compared to the placebo group. However, no significant differences were noted in other conditions such as chest or stomach pain, sensitivity to paints or fumes, anxiety, frustration, anorexia, energy levels, etc. Conclusions: These findings suggest that the beneficial antitussive properties of the herbal syrup persisted even after its discontinuation. Overall, the treatment led to an improvement in the QOL for the patients and a reduction in the frequency of cough episodes within the treated group.