Black seed oil, derived from Nigella sativa, has a long history of use in traditional medicine, particularly in Middle Eastern and South Asian cultures, for a variety of ailments including respiratory conditions. However, in recent years, several scientific studies have investigated its effects on allergic diseases, particularly allergic rhinitis and asthma. The active compound thymoquinone has been shown in laboratory and animal studies to have anti-inflammatory, antihistaminic, and immunomodulatory properties.

A handful of small human clinical trials have also been conducted. For example, a 2011 randomized, double-blind, placebo-controlled study published in the American Journal of Otolaryngology found that nasal application of black seed oil improved symptoms in patients with allergic rhinitis. Another study (2014, Phytotherapy Research) reported improved asthma control in patients using black seed oil as an adjunct therapy. Despite these promising findings, the evidence base is limited by small sample sizes, short study durations, and methodological weaknesses.

Overall, while preliminary scientific evidence suggests some benefit of black seed oil in supporting or treating respiratory allergies, larger and more rigorous clinical trials are needed before it can be recommended as a standard therapy. Its use is supported by both tradition and early scientific research, but the current scientific evidence is modest (rated 2/5).