Objectives. The aim of this study was to evaluate histological effects of a new combination folkloric medicinal plant extract on bone healing in premaxillary suture expansion in rats. 
 Materials and methods. Thirty male Sprague–Dawley rats were used in this study. Rats were evenly divided into three groups (one control and two experimental groups) of ten each. The animals were subjected to premaxillary suture expansion by helix springs. The only expansion group is defined as the control group (Group A). The experimental groups are defined as OstokinPlus-10 (Group B) and OstokinPlus-20 (Group C). In the experimental groups, 10 and 20 ml/kg OstokinPlus herbals were applied systemically after the expansion by use of an orogastric tube during the time of study. The springs were placed and activated to deliver a 30 cN force. After 5 days, the springs were removed and replaced with short lengths of rectangular retaining wire. Tooth separation was maintained for 15 days. After a consolidation period of 15 days, the animals were euthanatized and the maxillary bone containing the midpalatal suture cartilage was surgically removed. The specimens were prepared for histomorphometric assessment of the regenerated bone. 
 Results. The midpalatal suture was successfully distracted following application of the activated helix spring. The distracted premaxillary suture was filled with new bone formation and unorganized fibrous tissues. Newly formed bone percentage and the bone area were found to have significant differences (p< 0.05). For investigated parameters, Group B and Group C revealed more positive results than Group A. 
 Conclusion: OstokinPlus herbal had positive effects on bone healing and formation during premaxillary suture expansion