Peppermint leaf (Mentha × piperita) has a long history of traditional use for respiratory ailments, including bronchitis. In traditional herbal medicine, peppermint is valued for its soothing effects on the respiratory tract, its ability to act as an expectorant, and its mild antimicrobial properties. The main active component, menthol, is believed to help open airways, reduce cough, and ease breathing by providing a cooling sensation and possibly relaxing bronchial smooth muscle. Despite these traditional uses, scientific evidence specifically supporting peppermint leaf’s effectiveness for bronchitis is limited. Most modern studies focus on menthol (found in peppermint oil) rather than the whole leaf and typically investigate its effects in the context of inhaled formulations or topical rubs rather than oral ingestion of the leaf. Some studies suggest menthol can improve subjective feelings of nasal airflow and reduce cough reflex sensitivity, but these effects do not directly equate to clinically significant benefits in bronchitis treatment. There is little robust evidence from clinical trials supporting peppermint leaf as a primary treatment for bronchitis. In summary, while peppermint leaf has a traditional reputation for supporting respiratory health and easing symptoms of bronchitis, modern scientific validation is weak, and its use is primarily grounded in historical and anecdotal practices rather than strong clinical data.