Efficacy and safety of Xingqin Ganke Granules in postinfectious cough: study protocol for a multicenter, randomized, double-blind, placebo-controlled, dose-ranging phase II clinical trial

Previous studies have demonstrated that Herbal Xingqin Ganke Granules (XQGK) exhibit significant antitussive effects across various dosage groups and ameliorate airway hyperreactivity in mice models. However, the clinical efficacy in humans warrants further investigation through additional clinical trials. The present study aims to evaluate the efficacy and safety of XQGK in the treatment of postinfectious cough (PIC) with the syndrome of latent wind-heat in the lung.