Maidenhair Fern (Adiantum capillus-veneris) has a long history of use in traditional medicine for treating respiratory conditions, including coughs, particularly those described as "spastic" or associated with bronchial irritation. Historical herbal texts from Europe, the Middle East, and Asia often mention Maidenhair Fern as an ingredient in soothing syrups and expectorant remedies. The herb is believed to exert mild antitussive (cough-suppressing) and demulcent (soothing) effects, likely due to its mucilage content, which can coat the throat and reduce irritation. Various ethnobotanical reports cite its use for coughs, hoarseness, and mild bronchitis, either as a tea, syrup, or inhalation.

However, scientific validation is limited. There are a few in vitro and animal studies suggesting possible mild anti-inflammatory or antispasmodic effects, but robust clinical trials in humans are lacking. The evidence for efficacy is therefore largely traditional and anecdotal rather than based on high-quality scientific research. Regulatory agencies and modern pharmacopoeias do not generally recognize Maidenhair Fern as a proven treatment for cough. Thus, while its use for spastic cough has a strong tradition, it is not strongly supported by scientific evidence.