With regard to NAC inhibition on mucin hypersecretion caused by RSV infection [25], a previous study, similar as our study, reported that NAC reduce airway inflammation and responsiveness, goblet cell hyperplasia, and lung fibrosis by increasing levels of ROS, nuclear factor erythroid 2-related factor 2, and MUC5AC protein [26]. The gene discussed is MUC5AC; the disease is pulmonary fibrosis.