Efficacy of Nigella sativa in COVID-19 patients: a systematic review and meta-analysis

The COVID-19 pandemic has necessitated the investigation of potential treatment options to alleviate symptoms, reduce severe infection rates, and reduce mortality rates. Previous research on Nigella sativa, a phytomedicine with various therapeutic properties, has shown promise. This study aims to determine the efficacy of Nigella sativa as a treatment option for COVID-19 patients. We carried out a thorough systematic review of relevant literature from multiple databases until May 2024. Eligible studies were randomized controlled trials (RCTs) that investigated the efficacy of Nigella sativa as a treatment for COVID-19. We utilized the Cochrane Revised Risk of Bias 2 (ROB 2.0) to assess the quality of each included study. We carried out statistical analysis using RevMan version 5.4. The meta-analysis included a total of six studies with a total of 1595 COVID-19 patients. The use of Nigella sativa significantly reduced the severity of infection symptoms (OR = 0.08, 95% CI [0.02 to 0.25], P < 0.0001) and demonstrated a significant reduction in mortality rates (P = 0.383). Also, it significantly reduced CRP levels (MD = -3.287, 95% CI [-4.620 to -1.955], P < 0.00001) and the overall likelihood of patients experiencing headache (OR = 0.82, 95% CI [0.76 to 0.89], P < 0.00001). Furthermore, in contrast, our study found no statistically significant effect of Nigella sativa on common COVID-19 symptoms such as fever, cough, fatigue, and ferritin levels, a key inflammatory marker. Similarly, it had no effect on the occurrence of rhinorrhea or shortness of breath among patients. This meta-analysis provides evidence that Nigella sativa is effective as a potential treatment option for COVID-19 patients. The use of this phytomedicine significantly reduces the likelihood of patients experiencing headaches and severe infection symptoms.