Chronic skin ulcers are characterized by different etiological factors and may occur all over the body; the prevention and management of chronic skin ulcers in lower extremities continue to be severe problems in China. Wound healing in these injured tissues is a major health care problem with considerable socioeconomic impact. 1 According to data from epidemiological studies, the incidence of chronic ulcers in surgical hospitalized patients in China is 1.5% to 3.0% 2 ; the site distribution of these wounds varies with etiology. Of the 580 wounded areas in 489 patients, 366 were ulcerated on the lower extremities (63.10%), another 214 wounded sites (36.9%) were ulcerated in some other anatomic area, such as the upper extremities (17.93%), thoracic and abdominal regions (7.76%), the back (4.83%), and the head (6.38%). The principal cause of chronic ulcers is trauma, or traumatic wounds compounded by infections (67.48%). Diabetic ulcers, venous ulcers, and pressure ulcers account for 4.91%, 6.54%, and 9.20%, respectively, of ulcers. 2 The results from relative analysis of etiology, population, and ulcer anatomic distribution further confirmed the high incidence of these chronic skin ulcers in farmers and workers. It is considered that such workers engaged in manual labor are more susceptible to injury than others in the population. These results are quite different from the epidemiological results from Western societies, in that the main causes of wounds to the lower extremities in these countries are diabetes and age-induced diseases. 3,4 Another recent large-scale survey focused on diabetes and its complications revealed that the incidence of vascular complications in extremities in diabetes is 2.6% (type I diabetes) and 5.2% (type II diabetes), and 5.0% in all of diabetes. In all of these cases, 0.7% had dry gangrene, 1.9% had humid or wet gangrene, and 0.4% needed amputation. 5 The results are alarming and serve to warn us about the importance of prevention and management of lower extremity ulcers in the Chinese population. The biological processes of wound healing in chronic skin ulcers are quite different from those in acute skin wounds. In acute skin wounds, the woundhealing processes can be divided into 3 identifiable but overlapping phases, that is, inflammatory phase, proliferative phase, and maturation phase. In contrast, chronic skin ulcers are characterized by defective remodeling of the extracellular matrix, failure of reepithelization, and prolonged inflammation. For deep chronic wounds, such as pressure sores and diabetic foot ulcers, healing necessitates angiogenesis, deposition of the extracellular matrix, contraction, and epithelization. With the presence of such comorbidities as diabetes, infection, venous diseases, and malnutrition in patients who have previously undergone chemotherapy or radiotherapy, the chronic, nonhealing wounds will give both prolonged suffering to patients and frustration to attending physicians. 1,2 Thus, the wound-healing process for chronic wounds is more complicated as compared with the healing of acute wounds. The management of lower extremity ulcers is a ther