Study aim: Evaluation of Nigella sativa and honey combination effect on kidney stone expulsion in human Design: randomized clinical trial with control group - parallel groups, Settings and conduct: A clinical trial will be conducted on 40 eligible patients who will refer to the urology clinic of Dezful Ganjavian Hospital and will be identified by a sonographist that they have kidney stones smaller than 6 mm. They will be randomly assigned to control and treatment groups. The treatment group will take 8 grams of the product with one glass of warm water daily for one month. The control group will not receive medication. Both groups will drink 6-8 glasses of water per day. At the end, sonography will repeat. Blood and urine biochemical test, 24h urine volume and urine pH will determine before and after intervention too. At last the rate of stone expulsion will compare in two groups with SPSS 22 software. Participants/Inclusion and exclusion criteria: Inclusion criteria:age>18, stone size> 6 mm, Asymptomatic and without hydronephrosis, No need to medication; Exclusion criteria: Pregnancy, History of the complication or sensitivity to black seed, Receiving drugs that affect kidney stones, Use of stone crushing techniques, Diabetes Intervention groups: Conrol group: Receive 8 glasses of water for one month each day. Intervention group: Receive 8 glasses of water + 8 grams of product (po) for one month each day Main outcome variables: Excreted kidney stone number