(coriander) is prescribed as a treatment for headache in traditional Persian medicine. Several investigations have been carried out to find the medicinal properties of this plant. However, no study has evaluated the effectiveness of this plant on becoming migraine-free. Sixty-eight migraineurs were randomly allocated to two equal groups of and . Each received 500 mg of sodium valproate in addition to 15 mL of coriander or placebo syrup three times a day. We followed subjects and recorded their migraine duration in the 1, 2, 3, and 4 weeks. We applied an appropriate statistical model so as to consider special features of the data, which led to more accurate results using SAS 9.4 Our findings showed that the probability of being migraine-free was not only considerably higher in final weeks of the study (p<0.001) in all patients of the intervention group than placebo group, but it was also significantly higher in patients less than 30 years of age compared to patients older than 30 years old. Migraine duration in migraineurs using coriander syrup reduced considerably during the study (p<0.001). The finding of this study revealed that coriander has a significant effect both on the probability of being migraine free and the duration of migraine attacks. Its effects were more significant during the final weeks of study.© 2020 Iran University of Medical Sciences.