Efficacy of black seed (Nigella sativa L.) on kidney stone dissolution: A randomized, double-blind, placebo-controlled, clinical trial.

Preclinical studies have shown beneficial effects of black seed (Nigella sativa L.) in the prevention and treatment of renal stones. Hence, we designed a study to evaluate the renal-stone-dissolving efficacy of black seed. Sixty patients with renal stones were randomly enrolled in two arms of a randomized, triple-blind, placebo-controlled, clinical trial. The patients were treated by black seed capsules (500 mg) or placebo two times per day for 10 weeks. Patients were assessed in terms of size of renal stones by using sonography before and after intervention. In the black seed group, 44.4% of patients excreted their stones completely, and the size of the stones remained unchanged and decreased in 3.7% and 51.8% of patients, respectively. In contrast, in the placebo group, 15.3% of the patients excreted their stones completely, 11.5% had reduction in stone size, 15.3% had increase in stone size, and 57.6% had no change in their stone size. The difference in the mean size of renal stones after the study was significant between the two groups (p < 0.05). N. sativa L., as compared with placebo, is demonstrated to have significant positive effects on disappearance or reduction of size of kidney stones.