Reynoutria japonica for respiratory tract infections
This meta-analysis found herbal supplements with Reynoutria japonica (as well as a number of other herbs) to be beneficial for acute respiratory tract infections, but the quality of evidence was poor.
Vitamin D for preventing allergic diseases in early childhood
Smoking may increase the risk of several respiratory diseases, including severe COVID-19
Infant formulas with prebiotics, probiotics, or synbiotics for the prevention of respiratory tract infections
Is zinc useful for preventing or treating respiratory tract infections?