Nigella seed (Nigella sativa, also known as black seed or black cumin) has a long history of traditional use in various cultures for a range of ailments, including infectious diseases. More recently, modern scientific research has investigated its antimicrobial properties. Multiple in vitro and animal studies have demonstrated that thymoquinone, the main active component of Nigella seed oil, exhibits antibacterial activity against various pathogens such as Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. There is also evidence of antifungal and antiviral effects.

While laboratory and some animal studies are promising, clinical evidence in humans is less robust. Some small human studies and case reports suggest adjunctive benefits when Nigella sativa is used alongside conventional antibiotics, potentially reducing antibiotic resistance or enhancing efficacy. However, these studies are limited by size, quality, and lack of standardization.

Overall, the antimicrobial effects of Nigella seed are supported by a growing body of preclinical research, and there is a traditional basis for its use in infectious diseases. However, as a direct alternative to antibiotics in serious infections, there is currently insufficient high-quality human evidence. Thus, it may be considered as a supportive or adjunct therapy rather than a replacement for antibiotics.