Asafetida (Ferula asafoetida), a resin obtained from the roots of the plant, has a long history of use in traditional systems of medicine, particularly Ayurveda and Unani. In these traditions, asafetida has been used as an expectorant and antispasmodic agent to help alleviate symptoms of cough, including spastic or whooping cough (pertussis). Historical texts and ethnomedical reports describe the use of asafetida dissolved in water or as part of herbal formulations to reduce the severity and frequency of coughing fits, likely owing to its purported ability to relax bronchial muscles and thin mucus.

However, scientific validation for these uses remains limited. There are a few in vitro and animal studies that suggest asafetida may have antispasmodic, bronchodilatory, or anti-inflammatory effects, which could theoretically ease cough symptoms. Yet, controlled human clinical trials specifically evaluating its efficacy for spastic or whooping cough are lacking. Most of the supporting evidence is historical or anecdotal, and modern medical guidelines do not include asafetida as a recommended treatment for cough.

In summary, asafetida's use in treating spastic cough is primarily justified by traditional practices rather than robust scientific evidence.