Scallion (Allium fistulosum), also known as green onion or spring onion, has a long history of use in traditional Chinese medicine (TCM) for treating symptoms associated with respiratory ailments, including coughs, particularly those described as "spastic" or related to wind-cold invasion. In TCM, scallion is thought to have warming and dispersing properties, which are believed to help "release the exterior," promote sweating, and relieve symptoms like cough and nasal congestion. Ancient medical texts such as the Shen Nong Ben Cao Jing mention scallion as a remedy for coughs, especially in early-stage colds, due to its ability to stimulate circulation and clear blockages in the lung meridian.

However, while these traditional uses are well-documented, scientific validation for scallion's effectiveness specifically in treating cough—especially spastic or spasmodic cough—is limited. Although scallions contain sulfur compounds with mild antimicrobial and anti-inflammatory effects, there is a lack of robust clinical trials or pharmacological studies demonstrating significant efficacy in cough relief. Therefore, the evidence supporting its use is primarily traditional and historical, with limited support from modern scientific research.