Objective To evaluate the efficacy and safety of allogeneic platelet-rich gel( APG) in the treatment of refractory skin ulcer. Methods Based on the diagnostic standards for refractory skin ulcer and our inclusion and exclusion criteria,a total of 51 patients were enrolled in this study from May 2016 to March 2017. They were randomly divided into the experimental group( n = 26) and control group( n = 25).On the basis of bacterial culture and drug sensitive experiment before treatment,the patients of both gro...