In the Anglo-American literature, the importance of endogenous resistance in healing traumatic fractures is pointed out. Decades of experimental and practical experience using low-molecular extract of human placenta for the treatment of cancer to intensify endogenous resistance, motivated me to try this therapy on bone lesions in addition to the surgical treatment. Experiments showed an exorbitant increase of alkaline serum-phosphatase, a remarkable atypical intermediate callus phase, and an earlier solid healing than it was observed with comparable control groups. The question about the efficiency of this extract and the relation to problems of resistance cannot be answered and it is not clear, either if the extract could be described as a mesenchymal activator.