IRCT201212216975N4 IRCT 2013-03-20 Vice chancellor for research, Tabriz University of Medical Sciences Vitamin D supplementation for the treatment of Behcet's disease A randomized, double-blind controlled study of the efficacy of vitamin D supplementation compared with placebo on treatment of Behcet's disease 2013-04-05 anticipated 50 Complete https://irct.ir/trial/7435 interventional Randomization: Randomized, Blinding: Double blinded, Placebo: Used, Assignment: Parallel, Purpose: Treatment, Other design features: In order to eliminate the possibility of any probable bias due to the awareness of the patients and assessing physicians about the type of treatment, we will perform a double blind study. Vitamin D and placebo will be encapsulated so that the patients and assessing physicians will not have any knowledge about the type of the treatment. Randomization will be performed by the Randlist software and every patient will be entered in the treatment or control group. 2-3 Behcet's disease. Intervention 1: The treatment group will receive vitamin D soft gel (D-VITIN, Zahravi) containing 50000 units of cholecalciferol [(3β,5Z,7E)-9,10-secocholesta- 5,7,10(19)-trien-3-ol] one soft gel orally after meal every 2 weeks for 6 months. Intervention 2: The control group will receive one soft gel containing placebo orally after meal every 2 weeks for 6 months.