Objective: To observe the protective effect of Nigella sativa on number of cystic follicles in Letrozole induced polycystic ovaries in mice. Study Design: Laboratory based randomized control trial. Place and Duration of Study: Department of Anatomy. Army Medical College in collaboration with National Institute of Health from Nov 2014 to Nov 2015. https://www.roneverhart.com/Liftmaster-CSL24UL-Slide-Gate-Opener/