This paper presents an innovative method for the treatment of refractory wounds, starting with a blood unit, that is based on a biological approach. Local wound repair is one of the major unresolved clinical problems. Age, infection, clinical conditions such as diabetes mellitus, cardiac, renal, lung and liver failure, malnutrition and immunological deficiencies are among the reasons for wound repair delay or failure. Many chronic ulcers resist conventional treatment and do not heal for months and years, thus causing substantial morbidity and even mortality. The method for macrophage suspension treatment consists of introducing into the wound live cells that play a major role in the process of wound healing. The suspension is prepared from a blood unit of a healthy donor in a cost-effective, closed, sterile system. In the process of preparation, the macrophages are activated by hypo-osmotic shock to enhance their various functions in wound repair. The cells are applied to the wound either by local injection or by direct deposition into the wound. In most cases (90%), only one treatment is sufficient. Since 1995, macrophage suspensions have been used successfully in more than 1000 patients in several hospitals in Israel, without any side effects. Our results show that the use of a macrophage suspension is a safe and effective therapeutic strategy that shortens the healing period, reduces risk of complications and morbidity and improves the quality of life for long-suffering patients. This treatment requires no hospitalization and can be given on an ambulatory basis.