Nigella sativa seeds were one of the well-documented herbal products. Three reviewed randomized controlled trials reported that NS reduced covid-19 risk and could improve immune function. It was also helpful in upper respiratory infections such as asthma and bronchitis, with one RCT showing that honey and NS significantly improved symptoms, viral clearance, and mortality of COVID-19 patients. This review concludes that NS has a positive barrier effect on people at risk of acquiring a COVID-19 infection.