Nigella seed (Nigella sativa), also known as black cumin or black seed, has a long history of traditional use in various systems of medicine, particularly in the Middle East, South Asia, and North Africa. Historically, it has been used for a wide range of ailments, including those involving the respiratory tract and mucus membranes. Traditional texts, such as those from Unani, Ayurveda, and even medieval Islamic medicine, mention the use of nigella seed for conditions like cough, asthma, bronchitis, and general respiratory discomfort—all of which involve the mucus membranes of the respiratory tract.

The rationale behind its use often centers on its reputed anti-inflammatory, antimicrobial, and immunomodulatory properties, which may help soothe irritated mucus membranes and support respiratory health. Thymoquinone, one of its main bioactive compounds, has been studied for these properties, but direct clinical evidence specifically linking nigella seed to improvement of mucus membrane function remains limited. Some modern preliminary studies suggest that Nigella sativa oil may have beneficial effects in asthma and allergic rhinitis, both of which involve mucus membrane inflammation, but these studies are generally small and not conclusive.

Overall, the use of nigella seed to support mucus membranes is primarily rooted in traditional medicine, with some emerging but not definitive scientific evidence suggesting possible benefits.