The aim of this study was a histopathological evaluation of the effects of nano magnesium oxide and platelets-rich fibrin on induced radial fracture bone healing in local stray dogs. We used 18 adult animals weighing 17.5±0.6 kg and aged 2.0±0.1 years; these experimental animals were divided into three main equal groups. In the first group (Control), the fracture was left without treatment of any bioactive materials; in the second group (nano magnesium oxide), the fracture line was injected with 20µg of nano magnesium oxide, the third group (platelets rich fibrin) the fracture line was surrounded by platelet-rich fibrin. The bone specimens were taken from all experimental animals 6 and 10 weeks after the surgical operation. A Colorimetric method was used for measuring the alkaline phosphatase enzyme and calcium concentrations in all trial animals. The histopathological results at the 6th and 10th weeks showed that the best response was in the platelets-rich fibrin group, then the nano magnesium oxide group, and lastly, the control group according to the formation of fibrocartilaginous tissue, trabeculae, and woven bone. The concentration rates of alkaline phosphatase enzyme and calcium were increased in the weeks that followed the surgical operation. In conclusion of this study, platelets-rich fibrin and nano-magnesium oxide accelerated the healing of the radial fracture.