Background and aims Allergic rhinitis is the most common chronic and allergic disease, especially in children. This study aimed to investigate the anti-inflammatory effects of Nigella sativa and its effects on inflammatory factors in patients with allergic rhinitis symptoms and the process their clinical study charges. Setting The present study is a clinical trial that conducted as prospective and double blind with descriptive analytic. Materials and methods The sample included 66 patients (case and placebo) with allergic rhinitis exposed to N. sativa oil. Individual characteristics, including age and sex, and characteristics of the disease, including nasal congestion, runny nose, itchy nose, and sneezing attacks, were evaluated. From the start of the study, that is, day 0, up to the end of the study, that is, day 30, an observer completed the symptoms severity questionnaire. Statistical analysis Data were presented as means ± SEM. Comparisons between groups were performed by using paired Student t test. Differences were considered significant if P values are less than .05 and .01. Results In the present study, 66 patients with allergic rhinitis, including 22 males (33.3%) and 44 females (66.7%) with a mean age of 47.19 years, were included. Immunoglobulin E total of more than 100 was reported in 38 patients before treatment. Immunoglobulin E in nasal wash from 7 patients was observed and was not measurable in 59 cases. Only 6.1% of the study population had nasal mucosal eosinophil. Conclusion The results show that N. sativa could reduce the presence of the nasal mucosal congestion, nasal itching, runny nose, sneezing attacks, turbinate hypertrophy, and mucosal pallor during the first 2 weeks (day 15). The present findings are consistent with evidence that the antiallergic effects of N. sativa components could be attributed to allergic rhinitis. Moreover, N. sativa should be considered for treating allergic rhinitis when the effects of other antiallergic drugs need to be avoided.