Background: The restoration of bone continuity and bone union are complex processes, and their success is determined by the effectiveness of osteosynthesis. The use of plants for healing purposes predates human history and forms the source of current modern medicine The aim of this study: It was histological evaluation of effect of topical application of flavonoid on healing of induced bone defect in rabbit tibia. Material and method: Twenty-four Adult New Zealand rabbits used in this study, they were divided into four groups for the healing periods (3days, 1,2, and 4weeks) Two holes were induced in rabbit tibia one on the left side and has been left to heal normally as control. While, the other hole made on the right side filled with flavonoid extract regarded as experimental. Sacrificing of the animals were done according to the healing periods. Routine processing and sectioning technique was performed for histological and histomorphometric evaluation. Results: Histological findings revealed that progression of bone healing process was accelerated after flavonoid application as shown by examination of histological sections and results of statistical analysis that indicated increase of mean count difference of cells between control and experimental groups obviously noticed at early healing durations. Histomorphometric analysis for all bone parameters examined in this study, showed increase in mean count difference while bone marrow space decreased. Conclusion: The study revealed that topical application of flavonoid was effective in promoting bone healing process
