A method of treating a bone defect in a subject, comprising administering to a subject in need thereof at a bone defect site an effective amount of isolated somatic stem cells, wherein the somatic stem cells are about 2 to 8.0 μm in size and are Lgr5+ or CD349+.一種治療一個體內的骨骼缺損的方法,其包含投與有效量之經單離的體幹細胞至需要其之個體內的骨骼缺損處,其中該體幹細胞大小為大約2至8.0μm且為Lgr5+或CD349+。