Inhalation therapy for pulmonary fibrosis: chemical medicines and herbal medicines

Pulmonary fibrosis (PF) is a chronic, progressive, and irreversible pulmonary interstitial disease with unclear pathogenesis. Currently, there are few treatment options for managing PF. Inhalation therapy, as a routine treatment for respiratory diseases, is being used to study the treatment of PF. Some herbal medicines and their active ingredients have been reported to have anti-PF effects. This review aims to provide an overview of the latest developments in inhalation therapy, focusing on the utilization of chemical medicines and herbal medicines for the treatment of PF in both clinical practice and basic research. The inhalation of chemical drugs such as pirfenidone, nintedanib, N-acetylcysteine, and interferon-γ has been shown to demonstrate anti-PF effects. Additionally, the inhalation of various natural products derived from herbal medicines, encompassing polyphenols, alkaloids, flavonoids, saponins, terpenoids, and herbal extracts, contributes to the therapeutic management of PF through diverse mechanisms. The inhalation of both chemical and herbal medicines presents promising advantages in the treatment of PF. Further clinical trials are required to investigate the effectiveness, safety, and mechanism of action of inhalation therapy utilizing natural products derived from herbal medicines.